Biochar for Sustainable Crop Productivity and Soil Health

**3**

**Chapter 1**

**Abstract**

**1. Introduction**

Soil Properties

Biochar: A Sustainable Approach

for Improving Plant Growth and

Soil is the most important source and an abode for many nutrients and microflora. Due to rapid depletion of agricultural areas and soil quality by means of ever-increasing population and an excessive addition of chemical fertilizers, a rehabilitated attention is a need of the hour to maintain sustainable approaches in agricultural crop production. Biochar is the solid, carbon-rich material obtained by pyrolysis using different biomasses. It has been widely documented in previous studies that, the crop growth and yield can be increased by using biochar. This chapter exclusively summarizes the properties of biochar, its interaction with soil

microflora, and its role in plant growth promotion when added to the soil.

not only deficient in macronutrients like NPK but also in secondary nutrients (e.g. sulfur, calcium, and magnesium) and micronutrients (e.g. boron, zinc, copper, and iron) [5]. Thus, to fulfill the shortage, a large amount of chemical fertilizers is added to the soil; however, only a small percent of water-soluble nutrients are taken up by the plants and the rest are converted into insoluble forms, making continuous application necessary. Finally, the extensive use of chemical fertilizers has led to the deterioration of the environment causing infinite problems. It not only lowers the nutrient composition of the crops but also degrades the soil fertility in the long run [6, 7].

**Keywords:** biochar, pyrolysis, soil microflora, nutrients, plant growth promotion

Crop growth and productivity are strongly influenced by various biotic and abiotic stresses such as pests, weeds, drought, high salinity, extreme temperature, etc. and the soil quality [1]. Soil is also contaminated by heavy metals through various human activities [2], which affect plant growth and development and ultimately brings low yielding cropping systems. Mining is one of the important sources of heavy metal contamination in soil [3, 4]. The strength of soil is directly related to nutrient availability. Plants require a number of soil nutrients like nitrogen (N), phosphorus (P), and potassium (K) for their growth, but soil nutrient levels may decrease over time after crop harvesting, as nutrients are not returned to the soil. In India, the soil of many regions is

Besides fertilizers, pesticides are also the basic evil for agriculture, and the adverse

effects of pesticides on the environment are truly responsible for influencing the microbial properties of soil. High inputs of fertilizers and pesticides and their long persistence in the soil adversely affect the soil microflora, thereby disturbing soil

*Jyoti Rawat, Jyoti Saxena and Pankaj Sanwal*

#### **Chapter 1**

## Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties

*Jyoti Rawat, Jyoti Saxena and Pankaj Sanwal*

#### **Abstract**

Soil is the most important source and an abode for many nutrients and microflora. Due to rapid depletion of agricultural areas and soil quality by means of ever-increasing population and an excessive addition of chemical fertilizers, a rehabilitated attention is a need of the hour to maintain sustainable approaches in agricultural crop production. Biochar is the solid, carbon-rich material obtained by pyrolysis using different biomasses. It has been widely documented in previous studies that, the crop growth and yield can be increased by using biochar. This chapter exclusively summarizes the properties of biochar, its interaction with soil microflora, and its role in plant growth promotion when added to the soil.

**Keywords:** biochar, pyrolysis, soil microflora, nutrients, plant growth promotion

#### **1. Introduction**

Crop growth and productivity are strongly influenced by various biotic and abiotic stresses such as pests, weeds, drought, high salinity, extreme temperature, etc. and the soil quality [1]. Soil is also contaminated by heavy metals through various human activities [2], which affect plant growth and development and ultimately brings low yielding cropping systems. Mining is one of the important sources of heavy metal contamination in soil [3, 4]. The strength of soil is directly related to nutrient availability. Plants require a number of soil nutrients like nitrogen (N), phosphorus (P), and potassium (K) for their growth, but soil nutrient levels may decrease over time after crop harvesting, as nutrients are not returned to the soil. In India, the soil of many regions is not only deficient in macronutrients like NPK but also in secondary nutrients (e.g. sulfur, calcium, and magnesium) and micronutrients (e.g. boron, zinc, copper, and iron) [5]. Thus, to fulfill the shortage, a large amount of chemical fertilizers is added to the soil; however, only a small percent of water-soluble nutrients are taken up by the plants and the rest are converted into insoluble forms, making continuous application necessary. Finally, the extensive use of chemical fertilizers has led to the deterioration of the environment causing infinite problems. It not only lowers the nutrient composition of the crops but also degrades the soil fertility in the long run [6, 7].

Besides fertilizers, pesticides are also the basic evil for agriculture, and the adverse effects of pesticides on the environment are truly responsible for influencing the microbial properties of soil. High inputs of fertilizers and pesticides and their long persistence in the soil adversely affect the soil microflora, thereby disturbing soil

health and significantly reducing the total bacterial and fungal biomass [8]. Due to long-term treatment with inorganic fertilizers (N and NPK) and/or organic manures, a shift in structural diversity and dominant bacterial groups in agricultural soils has been recorded by Wu et al. [9]. Biofertilizers, on the other hand, can reenergize the soil by improving the soil fertility and hence can be used as a powerful tool for sustainable agriculture, rendering agro-ecosystems more stress-free. Additionally, the application of organic amendments to soils, from a remedial point of view, has typically been justified by their relatively low cost, which normally requires other forms of disposal (burial in a landfill, incineration, etc.). Soil amendments must possess properties such as high binding capacity and environmental safety and should have no negative effect on the soil structure, soil fertility, or the ecosystem on the whole [10]. The use of biochar has been accepted as a sustainable approach and a promising way to improve soil quality and remove heavy-metal pollutants from the soil [11].

Biochar is a carbon-rich organic material, an organic amendment, and a by-product derived from biomass by pyrolysis under high-temperature and lowoxygen conditions. Biochar is produced through a process called pyrolysis, which basically involves heating of biomass (such as wood, manure, or leaves) in complete or almost complete absence of oxygen, with oil and gas as co-products. However, the quantity of these materials produced depends on the processing conditions. Recently, it has been reported that biochar obtained from the carbonization of organic wastes can be a substitute that not only influences the sequestration of soil carbon but also modifies its physicochemical and biological properties [12, 13].

Biochar has the potential to produce farm-based renewable energy in an ecofriendly way. Specifically, the quality of biochar depends on several factors, such as the type of soil, metal, and the raw material used for carbonization, the pyrolysis conditions, and the amount of biochar applied to the soil [14]. In addition, the biochar amendment to the soil proved to be beneficial to improve soil quality and retain nutrients, thereby enhancing plant growth [15]. Since biochar contains organic matter and nutrients, its addition increased soil pH, electric conductivity (EC), organic carbon (C), total nitrogen (TN), available phosphorus (P), and the cation-exchange capacity (CEC) [16]. Earlier, Verheijen et al. [17] reported that the biochar application affected the toxicity, transport, and fate of various heavy metals in the soil due to improved soil absorption capacity. The presence of plant nutrients and ash in the biochar and its large surface area, porous nature, and the ability to act as a medium for microorganisms have been identified as the main reasons for the improvement in soil properties and increase in the absorption of nutrients by plants in soils treated with biochar [18]. Chan et al. [19] reported that biochar application decreased the tensile strength of soil cores, indicating that the use of biochar can reduce the risk of soil compaction. A lot has already been discussed on the benefits of inoculation of rhizobacteria in soil, but the addition of biochar can also provide more nutrients to the soil, thus benefiting the agricultural crops. The mixing of the plant growth-promoting microorganisms with biochar was referred to as the best combination for growth and yield of French beans by Saxena et al. [20].

Addition of biochar in the soil can be extremely useful to improve the soil quality, as well as to stimulate the plant growth, and thus, biochar can play an important role in developing a sustainable system of agriculture. Several uses and positive effects of biochar amendment have currently been considered as an effective method to reclaim the contaminated soil [21] and to achieve high crop yields without harming the natural environment. The positive influence of biochar on plant growth and soil quality suggests that using biochar is a good way to overcome nutrient deficiency, making it a suitable technique to improve farm-scale nutrient cycles. Therefore, a complete focus is been made to explore the positive effects of biochar amendment on soil stability and plant growth promotion.

**5**

250–500°C [34].

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

processing parameters dictate the properties of the biochar.

from maize stover was obtained by Peterson et al. [31].

Biochar is made up of elements such as carbon, hydrogen, sulfur, oxygen, and nitrogen as well as minerals in the ash fraction. It is produced during pyrolysis, a thermal decomposition of biomass in an oxygen-limited environment. Biochar is black, highly porous, and finely grained, with light weight, large surface area and pH, all of which have a positive effect on its application to soil. To address the major concern on quality of agricultural soil degradation, biochar is applied to the soil in order to enhance its quality. Biochar is stabilized biomass, which may be mixed into soil with intentional changes in the properties of the soil's atmosphere to increase crop productivity and to mitigate pollution. The raw material (biomass) used and

A wide range of organic materials are suitable as feedstock for the production of biochar. Biochar can be produced with raw materials such as grass, cow manure, wood chips, rice husk, wheat straw, cassava rhizome, and other agricultural residues [22, 23]. It was reported that the production of biochar with high nutrients depends on the type of raw material used and pyrolysis conditions [24]. Biochar is produced from the residual biomasses such as crop residues, manure, wood residues, and forests and green wastes using modern pyrolysis technology. Agricultural wastes (bark, straw, husks, seeds, peels, bagasse, sawdust, nutshells, wood shavings, animal beds, corn cobs and corn stalks, etc.), industrial wastes (bagasse, distillers' grain, etc.), and urban/municipal wastes [25, 26] have been extensively used, thus also achieving waste management through its production

Feedstocks currently used on a commercial scale include tree bark, wood chips, crop residues (nut shells, straw, and rice hulls), grass, and organic wastes including distillers' grain, bagasse from the sugarcane industry, mill waste, chicken litter, dairy manure, sewage sludge, and paper sludge [28–30]. A 40 wt.% yield of biochar

The biomass used for the production of biochar is mainly composed of cellulose, hemicellulose, and lignin polymers [32]. Among these, cellulose has been found to be the main component of most plant-derived biomasses, but lignin is also impor-

Biochar can be manufactured on a small scale using low-cost modified stoves or kilns or through large-scale, cost-intensive production, which utilizes larger pyrolysis plants and higher amounts of feedstocks. Biochar is produced from several biomass feedstocks through pyrolysis as discussed above, generating oil and gases as by-products [33]. The dry waste obtained is simply cut into small pieces to less than 3 cm prior to use. The feedstock is heated either without oxygen or with little oxygen at the temperatures of 350–700°C (662–1292°F). Pyrolysis is generally classified by the temperature and time duration for heating; fast pyrolysis takes place at temperatures above 500°C and typically happens on the order of seconds (heating rates ≥ 1000°C/min). This condition maximizes the generation of bio-oil. Slow pyrolysis, on the other hand, usually takes more time, from 30 min to a few hours for the feedstock to fully pyrolyze (heating rates ≤ 100°C/min)

and at the same time yields more biochar. The temperature range remains

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

**2. Biochar production and properties**

**2.1 Biomass as a raw material**

and use [27].

tant in woody biomass.

**2.2 Biochar production**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

#### **2. Biochar production and properties**

*Biochar - An Imperative Amendment for Soil and the Environment*

health and significantly reducing the total bacterial and fungal biomass [8]. Due to long-term treatment with inorganic fertilizers (N and NPK) and/or organic manures, a shift in structural diversity and dominant bacterial groups in agricultural soils has been recorded by Wu et al. [9]. Biofertilizers, on the other hand, can reenergize the soil by improving the soil fertility and hence can be used as a powerful tool for sustainable agriculture, rendering agro-ecosystems more stress-free. Additionally, the application of organic amendments to soils, from a remedial point of view, has typically been justified by their relatively low cost, which normally requires other forms of disposal (burial in a landfill, incineration, etc.). Soil amendments must possess properties such as high binding capacity and environmental safety and should have no negative effect on the soil structure, soil fertility, or the ecosystem on the whole [10]. The use of biochar has been accepted as a sustainable approach and a promising way to improve soil quality and remove heavy-metal pollutants from the soil [11]. Biochar is a carbon-rich organic material, an organic amendment, and a by-product derived from biomass by pyrolysis under high-temperature and lowoxygen conditions. Biochar is produced through a process called pyrolysis, which basically involves heating of biomass (such as wood, manure, or leaves) in complete or almost complete absence of oxygen, with oil and gas as co-products. However, the quantity of these materials produced depends on the processing conditions. Recently, it has been reported that biochar obtained from the carbonization of organic wastes can be a substitute that not only influences the sequestration of soil carbon but also modifies its physicochemical and biological properties [12, 13]. Biochar has the potential to produce farm-based renewable energy in an ecofriendly way. Specifically, the quality of biochar depends on several factors, such as the type of soil, metal, and the raw material used for carbonization, the pyrolysis conditions, and the amount of biochar applied to the soil [14]. In addition, the biochar amendment to the soil proved to be beneficial to improve soil quality and retain nutrients, thereby enhancing plant growth [15]. Since biochar contains organic matter and nutrients, its addition increased soil pH, electric conductivity (EC), organic carbon (C), total nitrogen (TN), available phosphorus (P), and the cation-exchange capacity (CEC) [16]. Earlier, Verheijen et al. [17] reported that the biochar application affected the toxicity, transport, and fate of various heavy metals in the soil due to improved soil absorption capacity. The presence of plant nutrients and ash in the biochar and its large surface area, porous nature, and the ability to act as a medium for microorganisms have been identified as the main reasons for the improvement in soil properties and increase in the absorption of nutrients by plants in soils treated with biochar [18]. Chan et al. [19] reported that biochar application decreased the tensile strength of soil cores, indicating that the use of biochar can reduce the risk of soil compaction. A lot has already been discussed on the benefits of inoculation of rhizobacteria in soil, but the addition of biochar can also provide more nutrients to the soil, thus benefiting the agricultural crops. The mixing of the plant growth-promoting microorganisms with biochar was referred to as the best

combination for growth and yield of French beans by Saxena et al. [20].

biochar amendment on soil stability and plant growth promotion.

Addition of biochar in the soil can be extremely useful to improve the soil quality, as well as to stimulate the plant growth, and thus, biochar can play an important role in developing a sustainable system of agriculture. Several uses and positive effects of biochar amendment have currently been considered as an effective method to reclaim the contaminated soil [21] and to achieve high crop yields without harming the natural environment. The positive influence of biochar on plant growth and soil quality suggests that using biochar is a good way to overcome nutrient deficiency, making it a suitable technique to improve farm-scale nutrient cycles. Therefore, a complete focus is been made to explore the positive effects of

**4**

Biochar is made up of elements such as carbon, hydrogen, sulfur, oxygen, and nitrogen as well as minerals in the ash fraction. It is produced during pyrolysis, a thermal decomposition of biomass in an oxygen-limited environment. Biochar is black, highly porous, and finely grained, with light weight, large surface area and pH, all of which have a positive effect on its application to soil. To address the major concern on quality of agricultural soil degradation, biochar is applied to the soil in order to enhance its quality. Biochar is stabilized biomass, which may be mixed into soil with intentional changes in the properties of the soil's atmosphere to increase crop productivity and to mitigate pollution. The raw material (biomass) used and processing parameters dictate the properties of the biochar.

#### **2.1 Biomass as a raw material**

A wide range of organic materials are suitable as feedstock for the production of biochar. Biochar can be produced with raw materials such as grass, cow manure, wood chips, rice husk, wheat straw, cassava rhizome, and other agricultural residues [22, 23]. It was reported that the production of biochar with high nutrients depends on the type of raw material used and pyrolysis conditions [24]. Biochar is produced from the residual biomasses such as crop residues, manure, wood residues, and forests and green wastes using modern pyrolysis technology. Agricultural wastes (bark, straw, husks, seeds, peels, bagasse, sawdust, nutshells, wood shavings, animal beds, corn cobs and corn stalks, etc.), industrial wastes (bagasse, distillers' grain, etc.), and urban/municipal wastes [25, 26] have been extensively used, thus also achieving waste management through its production and use [27].

Feedstocks currently used on a commercial scale include tree bark, wood chips, crop residues (nut shells, straw, and rice hulls), grass, and organic wastes including distillers' grain, bagasse from the sugarcane industry, mill waste, chicken litter, dairy manure, sewage sludge, and paper sludge [28–30]. A 40 wt.% yield of biochar from maize stover was obtained by Peterson et al. [31].

The biomass used for the production of biochar is mainly composed of cellulose, hemicellulose, and lignin polymers [32]. Among these, cellulose has been found to be the main component of most plant-derived biomasses, but lignin is also important in woody biomass.

#### **2.2 Biochar production**

Biochar can be manufactured on a small scale using low-cost modified stoves or kilns or through large-scale, cost-intensive production, which utilizes larger pyrolysis plants and higher amounts of feedstocks. Biochar is produced from several biomass feedstocks through pyrolysis as discussed above, generating oil and gases as by-products [33]. The dry waste obtained is simply cut into small pieces to less than 3 cm prior to use. The feedstock is heated either without oxygen or with little oxygen at the temperatures of 350–700°C (662–1292°F). Pyrolysis is generally classified by the temperature and time duration for heating; fast pyrolysis takes place at temperatures above 500°C and typically happens on the order of seconds (heating rates ≥ 1000°C/min). This condition maximizes the generation of bio-oil. Slow pyrolysis, on the other hand, usually takes more time, from 30 min to a few hours for the feedstock to fully pyrolyze (heating rates ≤ 100°C/min) and at the same time yields more biochar. The temperature range remains 250–500°C [34].

The type of biochar produced depends on two variables: the biomass being used and the temperature and rate of heating. High and low temperatures have an unequivocal effect on char yields. It has been noticed that at low temperature (<550°C), biochar has an amorphous carbon structure with a lower aromaticity than the biochar produced at high temperature [35]. High temperature leads to lower char yield in all pyrolysis reactions [36]. Peng et al. [37] reported the effect of charring duration on the yield of biochar; yield showing a decrease with increasing duration at the same temperature. The pyrolysis process seriously affects the quality of biochar and its potential value to agriculture in terms of agronomic performance or in carbon sequestration. The yield of biochar from slow pyrolysis of biomass has been stated to be in the range of 24–77% [38, 39] (**Figure 1**). The pyrolysis process can be shown as follows:

 Biomass (Solid) → Biochar + Liquid or oil (tars,water, etc.) + Volatile gases (CO2,CO,H2) (1)

#### **2.3 Physical, chemical and biological properties of biochar**

Biochar is a stable form of carbon and can last for thousands of years in the soil [40]. It is produced for the purpose of addition to soil as a means of sequestering carbon and improving soil quality. The conditions of pyrolysis and the materials used can significantly affect the properties of biochar. The physical properties of biochar contribute to its function as a tool for managing the environment. It has been reported that when biochar is used as a soil amendment, it stimulates soil fertility and improves soil quality by increasing soil pH, increasing the ability to retain moisture, attracting more useful fungi and other microbes, improving the ability of

**7**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

cation exchange, and preserving the nutrients in the soil [41]. Biochar reduces soil density and soil hardening, increases soil aeration and cation-exchange capacity, and changes the soil structure and consistency through the changes in physical and chemical properties. It also helps to reclaim degraded soils. It has shown a greater ability to adsorb cations per unit carbon as compared to other soil organic matters because of its greater surface area, negative surface charge, and charge density [42], thereby offering the possibility of improving yields [43]. Samples with a sufficient amount of stable carbon can be added to the soil to be sequestered; a high sorption surface of biochar can characterize it as a soil additive, competent of halting risk

The physical characteristics of biochar are directly and indirectly related to how they affect soil systems. Soils have their own physical properties depending on the nature of mineral and organic matter, their relative amounts, and how minerals and organic matter are related. When biochar is present in the soil mixture, its contribution to the physical nature of the system is significant, affecting the depth, texture, structure, porosity, and consistency by changing the surface area, pore and particle-size distribution, density, and packing [44]. The influence of biochar on physical properties of soil directly affects the growth of plants, since the depth of penetration and accessibility of air and water in the root zone is determined mainly by the physical composition of the soil horizons. This affects the soil's response to water, its aggregation, and work ability in soil preparation, dynamics, and permeability when swelling, as well as the ability to retain cations and response to changes at ambient temperature. The smaller the pores on biochar, the longer they can retain capillary soil water. The addition of biochar can reduce the effects of drought on crop productivity in drought-affected areas due to its moisture-retention capacity. It has been shown that it eliminates soil constraints that limit the growth of plants, and neutralizes acidic soil because of its basic nature [45]. Carbon dioxide and oxygen occupy air-filled spaces on the pores of biochar or can be chemosorbed on the surface. As biochar can contain nutrients, microorganisms, and syngases, it can also retain fertilizers in the soil longer than other soils and prevent it from leaching

As far as its chemical properties are concerned, biochar reduces soil acidity by increasing the pH (also called the liming effect) and helps the soil to retain nutrients and fertilizers [46]. The application of biochar improves soil fertility through two mechanisms: adding nutrients to the soil (such as K, to a limited extent P, and many micronutrients) or retaining nutrients from other sources, including nutrients from the soil itself. However, the main advantage is to retain nutrients from other sources. In most cases, the addition of biochar only has a net positive effect on the growth of crops if nutrients from other sources, such as inorganic or organic fertilizers, are used. Biochar increases the availability of C, N, Ca, Mg, K, and P to plants, because biochar absorbs and slowly releases fertilizers [47]. It also helps to prevent fertilizer drainage and leaching by allowing less fertilizer use and reducing agricultural pollution in the surrounding environment [48]. Biochar alleviates the impact of hazardous pesticides and complex nitrogen fertilizers from the soil, thus

Good healthy soil should include a wide and balanced variety of life forms, including bacteria, fungi, protozoa, nematodes, arthropods, and earthworms. Recently, biochar has been reported to increase the microbial respiration of the soil by creating space for soil microbes [49], and in turn the soil biodiversity and soil density increased. Biochar also served as a habitat for extra-radical fungal hyphae that sporulated in micropores due to lower competition from saprophytes and therefore served as an inoculum for arbuscular mycorrhizal fungi [50]. It is believed that biochar has a long average dwelling time in soil, ranging

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

into water sources such as rivers and lakes.

reducing the impact on the local environment.

elements in soil.

**Figure 1.** *Biochar production from different biomasses.*

#### *Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

cation exchange, and preserving the nutrients in the soil [41]. Biochar reduces soil density and soil hardening, increases soil aeration and cation-exchange capacity, and changes the soil structure and consistency through the changes in physical and chemical properties. It also helps to reclaim degraded soils. It has shown a greater ability to adsorb cations per unit carbon as compared to other soil organic matters because of its greater surface area, negative surface charge, and charge density [42], thereby offering the possibility of improving yields [43]. Samples with a sufficient amount of stable carbon can be added to the soil to be sequestered; a high sorption surface of biochar can characterize it as a soil additive, competent of halting risk elements in soil.

The physical characteristics of biochar are directly and indirectly related to how they affect soil systems. Soils have their own physical properties depending on the nature of mineral and organic matter, their relative amounts, and how minerals and organic matter are related. When biochar is present in the soil mixture, its contribution to the physical nature of the system is significant, affecting the depth, texture, structure, porosity, and consistency by changing the surface area, pore and particle-size distribution, density, and packing [44]. The influence of biochar on physical properties of soil directly affects the growth of plants, since the depth of penetration and accessibility of air and water in the root zone is determined mainly by the physical composition of the soil horizons. This affects the soil's response to water, its aggregation, and work ability in soil preparation, dynamics, and permeability when swelling, as well as the ability to retain cations and response to changes at ambient temperature. The smaller the pores on biochar, the longer they can retain capillary soil water. The addition of biochar can reduce the effects of drought on crop productivity in drought-affected areas due to its moisture-retention capacity. It has been shown that it eliminates soil constraints that limit the growth of plants, and neutralizes acidic soil because of its basic nature [45]. Carbon dioxide and oxygen occupy air-filled spaces on the pores of biochar or can be chemosorbed on the surface. As biochar can contain nutrients, microorganisms, and syngases, it can also retain fertilizers in the soil longer than other soils and prevent it from leaching into water sources such as rivers and lakes.

As far as its chemical properties are concerned, biochar reduces soil acidity by increasing the pH (also called the liming effect) and helps the soil to retain nutrients and fertilizers [46]. The application of biochar improves soil fertility through two mechanisms: adding nutrients to the soil (such as K, to a limited extent P, and many micronutrients) or retaining nutrients from other sources, including nutrients from the soil itself. However, the main advantage is to retain nutrients from other sources. In most cases, the addition of biochar only has a net positive effect on the growth of crops if nutrients from other sources, such as inorganic or organic fertilizers, are used. Biochar increases the availability of C, N, Ca, Mg, K, and P to plants, because biochar absorbs and slowly releases fertilizers [47]. It also helps to prevent fertilizer drainage and leaching by allowing less fertilizer use and reducing agricultural pollution in the surrounding environment [48]. Biochar alleviates the impact of hazardous pesticides and complex nitrogen fertilizers from the soil, thus reducing the impact on the local environment.

Good healthy soil should include a wide and balanced variety of life forms, including bacteria, fungi, protozoa, nematodes, arthropods, and earthworms. Recently, biochar has been reported to increase the microbial respiration of the soil by creating space for soil microbes [49], and in turn the soil biodiversity and soil density increased. Biochar also served as a habitat for extra-radical fungal hyphae that sporulated in micropores due to lower competition from saprophytes and therefore served as an inoculum for arbuscular mycorrhizal fungi [50]. It is believed that biochar has a long average dwelling time in soil, ranging

*Biochar - An Imperative Amendment for Soil and the Environment*

can be shown as follows:

The type of biochar produced depends on two variables: the biomass being used and the temperature and rate of heating. High and low temperatures have an unequivocal effect on char yields. It has been noticed that at low temperature (<550°C), biochar has an amorphous carbon structure with a lower aromaticity than the biochar produced at high temperature [35]. High temperature leads to lower char yield in all pyrolysis reactions [36]. Peng et al. [37] reported the effect of charring duration on the yield of biochar; yield showing a decrease with increasing duration at the same temperature. The pyrolysis process seriously affects the quality of biochar and its potential value to agriculture in terms of agronomic performance or in carbon sequestration. The yield of biochar from slow pyrolysis of biomass has been stated to be in the range of 24–77% [38, 39] (**Figure 1**). The pyrolysis process

Biomass (Solid) → Biochar + Liquid or oil (tars,water, etc.)

Biochar is a stable form of carbon and can last for thousands of years in the soil [40]. It is produced for the purpose of addition to soil as a means of sequestering carbon and improving soil quality. The conditions of pyrolysis and the materials used can significantly affect the properties of biochar. The physical properties of biochar contribute to its function as a tool for managing the environment. It has been reported that when biochar is used as a soil amendment, it stimulates soil fertility and improves soil quality by increasing soil pH, increasing the ability to retain moisture, attracting more useful fungi and other microbes, improving the ability of

**2.3 Physical, chemical and biological properties of biochar**

+ Volatile gases (CO2,CO,H2) (1)

**6**

**Figure 1.**

*Biochar production from different biomasses.*

from 1000 to 10,000 years, with an average of 5000 years [51–53]. However, its recalcitrance and physical nature present significant impediment to the evaluation of long-term stability [43]. The commercially available soil microbes which can be used for inoculation include *Azospirillum* sp., *Azotobacter* sp., *Bacillus thuringiensis*, *B. megaterium*, *Glomus fasciculatum*, *G. mosseae*, *Pseudomonas fluorescens*, *Rhizobium* sp., and *Trichoderma viride* [54].

#### **3. Biochar as a soil amendment**

The issues as food security, declining soil fertility, climate change, and profitability are the driving forces behind the introduction of new technologies or new farming systems. The amendment of soils for their remediation aims at reducing the risk of pollutant transfer to waters or receptor organisms in proximity. The organic material such as biochar may serve as a popular choice for this purpose because its source is biological and it may be directly applied to soils with little pretreatment [55]. There are two aspects which make biochar amendment superior to other organic materials: the first is the high stability against decay, so that it can remain in soil for longer times providing long-term benefits to soil and the second is having more capability to retain the nutrients. Biochar amendment improves soil quality by increasing soil pH, moisture-holding capacity, cation-exchange capacity, and microbial flora [56].

The addition of biochar to the soil has shown the increase in availability of basic cations as well as in concentrations of phosphorus and total nitrogen [57, 58]. Typically, alkaline pH and mineral constituents of biochar (ash content, including N, P, K, and trace elements) can provide important agronomic benefits to many soils, at least in the short to medium term. When biochar with a higher pH value was applied to the soil, the amended soil generally became less acidic [59]. Acidic biochar could also increase soil pH when used in soil with a lower pH value. The pH of biochar, similar to the other properties, is influenced by the type of feedstock, production temperature, and production duration.

Another valuable property of biochar is suppression of emissions of greenhouse gases in soil. It has also been demonstrated by Zhang et al. [60] that the emissions of methane and nitrous oxide were reduced from agricultural soils, which may have additional climate mitigation effects, since these are potent greenhouse gases. Spokas et al. [61] reported reduced carbon dioxide production by addition of different concentrations of biochar ranging from 2 to 60% (w/w), suppressed nitrous oxide production at levels higher than 20% (w/w), and ambient methane oxidation at all levels over unamended soil.

Several studies have shown the control of pathogens by the use of biochar in agricultural soil. Bonanomi et al. [62] reported that biochar is effective against both air-borne (e.g. *Botrytis cinerea* and different species of powdery mildew) and soilborne pathogens (e.g. *Rhizoctonia solani* and species of *Fusarium* and *Phytophthora*). The application of the biochar derived from citrus wood was capable of controlling air-borne gray mold, *Botrytis cinerea* on *Lycopersicon esculentum*, *Capsicum annuum* and *Fragaria × ananassa*. Although there is a shortage of published data on the effects of biochar on soil-borne pathogens, evidence given by Elmer et al. [63] has shown that the control of certain pathogens may be possible. The addition of biochar in 0.32, 1.60, and 3.20% (w/w) to asparagus soils infested with *Fusarium* has augmented the biomass of asparagus plants and reduced *Fusarium* root rot disease [63]. Similarly, *Fusarium* root rot disease in asparagus was also reduced by biochar inoculated with mycorrhizal fungi [64]. A study of suppression of bacterial wilt in tomatoes showed that biochar obtained from municipal organic waste reduced the

**9**

impact of biochar.

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

in the physical, chemical, and biological characteristics of the soil.

the subsequent degradation of these waters from agricultural activity.

action of biochar in the soil be understood before its application.

**4. Stimulation of soil microflora and plant growth**

incidence of the disease in *Ralstonia solanacearum* infested soil [65]. Ogawa [66] advocated the use of biochars and biochar amended composts for controlling the diseases caused by bacteria and fungi in soil. The disease suppression mechanism has been attributed to the presence of calcium compounds, as well as improvements

The prevention of 'diffuse water pollution' through ammonium sorption or the mediation of the dynamics of a soil solution containing nitrate, phosphorus, and other nutrients has been extensively studied. The application of biochar to soil can influence a wide range of soil constraints such as high availability of Al [67], soil structure and nutrient availability [24], bioavailability of organic [68] and inorganic pollutants [69], cation-exchange capacity (CEC), and retention of nutrients [70, 71]. Biochar can also adsorb pesticides, nutrients, and minerals in the soil, preventing the movement of these chemicals into surface water or groundwater and

Xie et al. [72] reported that biochar amendment enhanced soil fertility and crop

production, particularly in soils with low nutrients. However, in soils with high fertility, no noticeable increase in production was noticed, and some studies even reported inhibition of plant growth. The observations of Taghizadeh-Toosi et al. [73] indicated that ammonia adsorbed by biochar could be later released to the soil. Saarnio et al. [74] showed that biochar application along with fertilizers can lead to better plant growth, but sometimes a negative effect was also observed without fertilization due to reduced bio-availability through sorption of nitrogen. It has been shown that application of biochar in the soil has a positive to neutral and even negative impact on crop production. Hence, it is crucial that the mechanisms for

The consequence of biochar addition on plant productivity depends on the amount added. Recommended application rates for any soil amendment should be based on extensive field testing. At present, insufficient data are available for obtaining general recommendations. In addition, biochar materials can vary greatly in their characteristics, so the nature of the particular biochar material (e.g. pH and ash content) also influences the application rate. Several studies have reported a positive effect of using biochar on crop yields with rates of 5–50 tonnes per hectare with appropriate nutrient management. The experiments conducted by Rondon et al. [75] resulted in a decrease in crop yield in a pot experiment with nutrient deficient soil amended with biochar at the rate of 165 tonnes per hectare. An experiment conducted in the United States showed that peanut hull and pine chip biochar, applied to 11 and 22 tonnes per hectare, could reduce corn yields below those obtained in the control plots with standard fertilizer management [76]. Thus, the control of the rate of application of biochar is necessary to prevent the negative

There are several reports which show that biochar has the capability to stimulate the soil microflora, which results in greater accumulation of carbon in soil. Besides adsorbing organic substances, nutrients, and gases, biochars are likely to offer a habitat for bacteria, actinomycetes and fungi [64]. It has been suggested that faster heating of biomass (fast pyrolysis) will lead to the formation of biochar with fewer microorganisms, smaller pore size, and more liquid and gas components [77]. The enhancement of water retention after biochar application in soil has been well established [78], and this may affect the soil microbial populations. Biochar provides a suitable habitat for a large and diverse group of soil microorganisms,

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

#### *Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

incidence of the disease in *Ralstonia solanacearum* infested soil [65]. Ogawa [66] advocated the use of biochars and biochar amended composts for controlling the diseases caused by bacteria and fungi in soil. The disease suppression mechanism has been attributed to the presence of calcium compounds, as well as improvements in the physical, chemical, and biological characteristics of the soil.

The prevention of 'diffuse water pollution' through ammonium sorption or the mediation of the dynamics of a soil solution containing nitrate, phosphorus, and other nutrients has been extensively studied. The application of biochar to soil can influence a wide range of soil constraints such as high availability of Al [67], soil structure and nutrient availability [24], bioavailability of organic [68] and inorganic pollutants [69], cation-exchange capacity (CEC), and retention of nutrients [70, 71]. Biochar can also adsorb pesticides, nutrients, and minerals in the soil, preventing the movement of these chemicals into surface water or groundwater and the subsequent degradation of these waters from agricultural activity.

Xie et al. [72] reported that biochar amendment enhanced soil fertility and crop production, particularly in soils with low nutrients. However, in soils with high fertility, no noticeable increase in production was noticed, and some studies even reported inhibition of plant growth. The observations of Taghizadeh-Toosi et al. [73] indicated that ammonia adsorbed by biochar could be later released to the soil. Saarnio et al. [74] showed that biochar application along with fertilizers can lead to better plant growth, but sometimes a negative effect was also observed without fertilization due to reduced bio-availability through sorption of nitrogen. It has been shown that application of biochar in the soil has a positive to neutral and even negative impact on crop production. Hence, it is crucial that the mechanisms for action of biochar in the soil be understood before its application.

The consequence of biochar addition on plant productivity depends on the amount added. Recommended application rates for any soil amendment should be based on extensive field testing. At present, insufficient data are available for obtaining general recommendations. In addition, biochar materials can vary greatly in their characteristics, so the nature of the particular biochar material (e.g. pH and ash content) also influences the application rate. Several studies have reported a positive effect of using biochar on crop yields with rates of 5–50 tonnes per hectare with appropriate nutrient management. The experiments conducted by Rondon et al. [75] resulted in a decrease in crop yield in a pot experiment with nutrient deficient soil amended with biochar at the rate of 165 tonnes per hectare. An experiment conducted in the United States showed that peanut hull and pine chip biochar, applied to 11 and 22 tonnes per hectare, could reduce corn yields below those obtained in the control plots with standard fertilizer management [76]. Thus, the control of the rate of application of biochar is necessary to prevent the negative impact of biochar.

#### **4. Stimulation of soil microflora and plant growth**

There are several reports which show that biochar has the capability to stimulate the soil microflora, which results in greater accumulation of carbon in soil. Besides adsorbing organic substances, nutrients, and gases, biochars are likely to offer a habitat for bacteria, actinomycetes and fungi [64]. It has been suggested that faster heating of biomass (fast pyrolysis) will lead to the formation of biochar with fewer microorganisms, smaller pore size, and more liquid and gas components [77]. The enhancement of water retention after biochar application in soil has been well established [78], and this may affect the soil microbial populations. Biochar provides a suitable habitat for a large and diverse group of soil microorganisms,

*Biochar - An Imperative Amendment for Soil and the Environment*

sp., and *Trichoderma viride* [54].

**3. Biochar as a soil amendment**

microbial flora [56].

from 1000 to 10,000 years, with an average of 5000 years [51–53]. However, its recalcitrance and physical nature present significant impediment to the evaluation of long-term stability [43]. The commercially available soil microbes which can be used for inoculation include *Azospirillum* sp., *Azotobacter* sp., *Bacillus thuringiensis*, *B. megaterium*, *Glomus fasciculatum*, *G. mosseae*, *Pseudomonas fluorescens*, *Rhizobium*

The issues as food security, declining soil fertility, climate change, and profitability are the driving forces behind the introduction of new technologies or new farming systems. The amendment of soils for their remediation aims at reducing the risk of pollutant transfer to waters or receptor organisms in proximity. The organic material such as biochar may serve as a popular choice for this purpose because its source is biological and it may be directly applied to soils with little pretreatment [55]. There are two aspects which make biochar amendment superior to other organic materials: the first is the high stability against decay, so that it can remain in soil for longer times providing long-term benefits to soil and the second is having more capability to retain the nutrients. Biochar amendment improves soil quality by increasing soil pH, moisture-holding capacity, cation-exchange capacity, and

The addition of biochar to the soil has shown the increase in availability of basic cations as well as in concentrations of phosphorus and total nitrogen [57, 58]. Typically, alkaline pH and mineral constituents of biochar (ash content, including N, P, K, and trace elements) can provide important agronomic benefits to many soils, at least in the short to medium term. When biochar with a higher pH value was applied to the soil, the amended soil generally became less acidic [59]. Acidic biochar could also increase soil pH when used in soil with a lower pH value. The pH of biochar, similar to the other properties, is influenced by the type of feedstock,

Another valuable property of biochar is suppression of emissions of greenhouse gases in soil. It has also been demonstrated by Zhang et al. [60] that the emissions of methane and nitrous oxide were reduced from agricultural soils, which may have additional climate mitigation effects, since these are potent greenhouse gases. Spokas et al. [61] reported reduced carbon dioxide production by addition of different concentrations of biochar ranging from 2 to 60% (w/w), suppressed nitrous oxide production at levels higher than 20% (w/w), and ambient methane oxidation

Several studies have shown the control of pathogens by the use of biochar in agricultural soil. Bonanomi et al. [62] reported that biochar is effective against both air-borne (e.g. *Botrytis cinerea* and different species of powdery mildew) and soilborne pathogens (e.g. *Rhizoctonia solani* and species of *Fusarium* and *Phytophthora*). The application of the biochar derived from citrus wood was capable of controlling air-borne gray mold, *Botrytis cinerea* on *Lycopersicon esculentum*, *Capsicum annuum* and *Fragaria × ananassa*. Although there is a shortage of published data on the effects of biochar on soil-borne pathogens, evidence given by Elmer et al. [63] has shown that the control of certain pathogens may be possible. The addition of biochar in 0.32, 1.60, and 3.20% (w/w) to asparagus soils infested with *Fusarium* has augmented the biomass of asparagus plants and reduced *Fusarium* root rot disease [63]. Similarly, *Fusarium* root rot disease in asparagus was also reduced by biochar inoculated with mycorrhizal fungi [64]. A study of suppression of bacterial wilt in tomatoes showed that biochar obtained from municipal organic waste reduced the

production temperature, and production duration.

at all levels over unamended soil.

**8**

although the interaction of biochar with soil microorganisms is a complex phenomenon. Many studies reported that addition of biochar along with phosphate solubilizing fungal strains promoted growth and yield of *Vigna radiata* and *Glycine max* plants, with better performances than control or those observed when the strains and biochar are used separately [20, 79, 80].

The use of biochar increased mycorrhizal growth in clover bioassay plants by providing the suitable conditions for colonization of plant roots [81]. Warnock et al. [82] summarized four mechanisms by which biochar can affect functioning of mycorrhizal fungi: (i) changes in the physical and chemical properties of soil, (ii) indirect effects on mycorrhizae through exposure to other soil microbes, (iii) plantfungus signaling interference and detoxification of toxic chemicals on biochar, and (iv) providing shelter from mushroom browsers. Carrots and legumes grown on steep slopes and in soils with less than 5.2 pH showed significantly improved growth by the addition of biochar [83]. It was found that biochar increased the biological N2 fixation (BNF) of *Phaseolus vulgaris* [75] mainly due to greater availability of micronutrients after application of biochar. Lehmann et al. [58] reported that biochar reduced leaching of NH4 + by supporting it in the surface soil where it was available for plant uptake. Mycorrhizal fungi were often included in crop management strategies as they were widely used as supplements for soil inoculum [84]. When using both biochar and mycorrhizal fungi in accordance with management practices, it is obviously possible to use potential synergism that can positively affect soil quality. The fungal hyphae and bacteria that colonize the biochar particles (or other porous materials) may be protected from soil predators such as mites, Collembola and larger (>16 μm in diameter) protozoans and nematodes [85–87].

Biochar can increase the value of non-harvested agricultural products [88] and promote the plant growth [58, 89]. A single application of 20 t ha<sup>−</sup><sup>1</sup> biochar to a Colombian savanna soil resulted in an increase in maize yield by 28–140% as compared with the unamended control in the 2nd to 4th years after application [90]. With the addition of biochar at the rate of 90 g kg<sup>−</sup><sup>1</sup> to tropical, low-fertile ferralsol, not only the proportion of N fixed by bean plants (*Phaseolus vulgaris*) increased from 50% (without biochar) to 72%, but also the production of biomass and bean yield were improved significantly [75]. When biochar was applied to the soil, a higher grain yield of upland rice (*Oryza sativa*) was obtained in northern Laos sites with low P availability [91, 92]. Many of these effects are interrelated and may act synergistically to improve crop productivity. Often there has been a reported increase in yields, which is directly related to the addition of biochar as compared to the control (without biochar) [58]. However, in some cases, growth was found to be depressed [93].

The direct beneficial effects of biochar addition for the availability of nutrients are largely due to the higher content of potassium, phosphorus, and zinc availability and, to a lesser extent, calcium and copper [58]. Few studies have examined the potential for amending biochar in soil to impact plant resistance to pathogens. With reference to soil pathogens principally concerned with the effect of AM fungal inoculations on asparagus tolerance to the soil borne root rot pathogen *Fusarium*, Matsubara et al. [94] demonstrated that charcoal amendments had a suppressive effect on pathogens. One more study that supported these earlier findings stated that biochar made from ground hardwood added to asparagus field soil led to a decrease in root lesions caused by *Fusarium oxysporum*, *F. asparagi,* and *F. proliferatum* compared to the non-amended control [95]. Biochar reduces the need for fertilizer, which results in reduction in emissions from fertilizer production, and turning the agricultural waste into biochar also reduces the level of methane (another potent greenhouse gas) caused by the natural decomposition of waste.

**11**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

Mixing biochar with other soil amendments such as manure, compost, or lime before soil application can improve efficiency by reducing the number of field operations required. Since biochar has been shown to sorb nutrients and protect them from leaching [70, 96], mixing of biochar may improve the efficiency of manure and other amendments. However, Kammann et al. [97] acknowledged in their recent review that very few studies that directly combined organic amendments with biochars were available. They found that co-composted biochars had a remarkable plant growth-promoting effect as compared to biochars when used pure, but no-systematic studies have been done to understand the interactive effects of biochars with non-pyrogenic organic amendments (NPOAs). Biochar can also be mixed with liquid manures and used as slurry. Additionally, combined biochar and compost applications have numerous advantages over mixing of biochar or compost with soil separately. These benefits, according to Liu et al. [98], include more efficient use of nutrients, biological activation of biochar, an enhanced supply of plant-available nutrients by biological nitrogen fixation, reduction of nutrient leaching, and the contribution of combined nutrients in comparison to a single application of compost and biochar. Diminutive biochars are most likely best suited for this type of application. Biochar was also mixed with manure in ponds and potentially reduced losses of nitrogen gas were recorded same as when it was

The problem of the depletion of agricultural land as a result of the pressure caused by the ever-growing population necessitated the sustainable practice of crop production. It was suggested to use biochar as a means of remediating contaminated agricultural soil, improving soil fertility by reducing the acidity, and increasing the availability of nutrients. Thus, addition of biochar to the soil can be one of the best practices to overcome any biotic stress in soil and to increase the crop productivity. The positive effects of biochar on the interactions between soil-plant-water caused better photosynthetic performance and improved nitrogen and water use efficiency. Hence, it can be concluded by this comprehensive review that biochar has the potential to improve the properties of soil, microbial abundance, biological nitrogen fixation, and plant growth. Therefore, it is recommended to use biochar as

a soil amendment for long-term carbon sink restoration.

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

applied to soil [99, 100].

**6. Conclusion**

**5. Mixing biochar with other amendments**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

#### **5. Mixing biochar with other amendments**

Mixing biochar with other soil amendments such as manure, compost, or lime before soil application can improve efficiency by reducing the number of field operations required. Since biochar has been shown to sorb nutrients and protect them from leaching [70, 96], mixing of biochar may improve the efficiency of manure and other amendments. However, Kammann et al. [97] acknowledged in their recent review that very few studies that directly combined organic amendments with biochars were available. They found that co-composted biochars had a remarkable plant growth-promoting effect as compared to biochars when used pure, but no-systematic studies have been done to understand the interactive effects of biochars with non-pyrogenic organic amendments (NPOAs). Biochar can also be mixed with liquid manures and used as slurry. Additionally, combined biochar and compost applications have numerous advantages over mixing of biochar or compost with soil separately. These benefits, according to Liu et al. [98], include more efficient use of nutrients, biological activation of biochar, an enhanced supply of plant-available nutrients by biological nitrogen fixation, reduction of nutrient leaching, and the contribution of combined nutrients in comparison to a single application of compost and biochar. Diminutive biochars are most likely best suited for this type of application. Biochar was also mixed with manure in ponds and potentially reduced losses of nitrogen gas were recorded same as when it was applied to soil [99, 100].

#### **6. Conclusion**

*Biochar - An Imperative Amendment for Soil and the Environment*

and biochar are used separately [20, 79, 80].

+

With the addition of biochar at the rate of 90 g kg<sup>−</sup><sup>1</sup>

larger (>16 μm in diameter) protozoans and nematodes [85–87].

promote the plant growth [58, 89]. A single application of 20 t ha<sup>−</sup><sup>1</sup>

reduced leaching of NH4

although the interaction of biochar with soil microorganisms is a complex phenomenon. Many studies reported that addition of biochar along with phosphate solubilizing fungal strains promoted growth and yield of *Vigna radiata* and *Glycine max* plants, with better performances than control or those observed when the strains

The use of biochar increased mycorrhizal growth in clover bioassay plants by providing the suitable conditions for colonization of plant roots [81]. Warnock et al. [82] summarized four mechanisms by which biochar can affect functioning of mycorrhizal fungi: (i) changes in the physical and chemical properties of soil, (ii) indirect effects on mycorrhizae through exposure to other soil microbes, (iii) plantfungus signaling interference and detoxification of toxic chemicals on biochar, and (iv) providing shelter from mushroom browsers. Carrots and legumes grown on steep slopes and in soils with less than 5.2 pH showed significantly improved growth by the addition of biochar [83]. It was found that biochar increased the biological N2 fixation (BNF) of *Phaseolus vulgaris* [75] mainly due to greater availability of micronutrients after application of biochar. Lehmann et al. [58] reported that biochar

for plant uptake. Mycorrhizal fungi were often included in crop management strategies as they were widely used as supplements for soil inoculum [84]. When using both biochar and mycorrhizal fungi in accordance with management practices, it is obviously possible to use potential synergism that can positively affect soil quality. The fungal hyphae and bacteria that colonize the biochar particles (or other porous materials) may be protected from soil predators such as mites, Collembola and

Biochar can increase the value of non-harvested agricultural products [88] and

Colombian savanna soil resulted in an increase in maize yield by 28–140% as compared with the unamended control in the 2nd to 4th years after application [90].

not only the proportion of N fixed by bean plants (*Phaseolus vulgaris*) increased from 50% (without biochar) to 72%, but also the production of biomass and bean yield were improved significantly [75]. When biochar was applied to the soil, a higher grain yield of upland rice (*Oryza sativa*) was obtained in northern Laos sites with low P availability [91, 92]. Many of these effects are interrelated and may act synergistically to improve crop productivity. Often there has been a reported increase in yields, which is directly related to the addition of biochar as compared to the control (without biochar) [58]. However, in some cases, growth was found to be

The direct beneficial effects of biochar addition for the availability of nutrients are largely due to the higher content of potassium, phosphorus, and zinc availability and, to a lesser extent, calcium and copper [58]. Few studies have examined the potential for amending biochar in soil to impact plant resistance to pathogens. With reference to soil pathogens principally concerned with the effect of AM fungal inoculations on asparagus tolerance to the soil borne root rot pathogen *Fusarium*, Matsubara et al. [94] demonstrated that charcoal amendments had a suppressive effect on pathogens. One more study that supported these earlier findings stated that biochar made from ground hardwood added to asparagus field soil led to a decrease in root lesions caused by *Fusarium oxysporum*, *F. asparagi,* and *F. proliferatum* compared to the non-amended control [95]. Biochar reduces the need for fertilizer, which results in reduction in emissions from fertilizer production, and turning the agricultural waste into biochar also reduces the level of methane (another potent greenhouse gas) caused by the

by supporting it in the surface soil where it was available

biochar to a

to tropical, low-fertile ferralsol,

**10**

natural decomposition of waste.

depressed [93].

The problem of the depletion of agricultural land as a result of the pressure caused by the ever-growing population necessitated the sustainable practice of crop production. It was suggested to use biochar as a means of remediating contaminated agricultural soil, improving soil fertility by reducing the acidity, and increasing the availability of nutrients. Thus, addition of biochar to the soil can be one of the best practices to overcome any biotic stress in soil and to increase the crop productivity. The positive effects of biochar on the interactions between soil-plant-water caused better photosynthetic performance and improved nitrogen and water use efficiency. Hence, it can be concluded by this comprehensive review that biochar has the potential to improve the properties of soil, microbial abundance, biological nitrogen fixation, and plant growth. Therefore, it is recommended to use biochar as a soil amendment for long-term carbon sink restoration.

*Biochar - An Imperative Amendment for Soil and the Environment*

### **Author details**

Jyoti Rawat1 , Jyoti Saxena<sup>2</sup> \* and Pankaj Sanwal<sup>2</sup>

1 Department of Biotechnology, Kumaun University, Bhimtal Campus, Nainital, India

2 Biochemical Engineering Department, B.T. Kumaon Institute of Technology, Dwarahat, India

\*Address all correspondence to: saxenajyoti30@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**13**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

microbial in arable soil under different long-term fertilization regimes in the Loess Plateau of China. African Journal of Microbiology Research.

[10] Paz-Ferreiro J, Lu H, Fu S, Méndez A, Gascó G. Use of phytoremediation and biochar to remediate heavy metal polluted soils: A review. Solid Earth Discussions. 2013;**5**:2155-2179

[11] Lahori AH, Zhanyu G, Zhang Z, li R, Mahar A, Awasthi M, et al. Use of biochar as an amendment for remediation of heavy metalcontaminated soils: Prospects and challenges. Pedosphere.

[12] García AC, de Souza LGA, Pereira MG, Castro RN, García-Mina JM, Zonta E, et al. Structure-property-function relationship in humic substances to explain the biological activity in plants. Scientific Reports. 2016;**6**:20798. DOI:

[13] Zhang R, Zhang Y, Song L, Song X, Hanninen H, Wu J. Biochar enhances nut quality of *Torreya grandis* and soil fertility under simulated nitrogen deposition. Forest Ecology and Management. 2017;**391**:321-329

[14] Debela F, Thring RW, Arocena JM. Immobilization of heavy metals by co-pyrolysis of contaminated soil with woody biomass. Water, Air, and Soil Pollution. 2012;**223**:1161-1170

[15] Bonanomi G, Ippolito F, Cesarano G, Nanni B, Lombardi N, Rita A, et al. Biochar as plant growth promoter: Better off alone or mixed with organic amendments? Frontiers in Plant Science. 2017;**8**:1570. DOI: 10.3389/

[16] Dume B, Mosissa T, Nebiyu A. Effect of biochar on soil properties

2012;**6**:6152-6164

2017;**27**:991-1014

10.1038/srep20798

fpls.2017.01570

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

[1] Thalmann M, Santelia D. Starch as a determinant of plant fitness under abiotic stress. The New Phytologist.

[2] Moon DH, Park JW, Chang YY, Ok YS, Lee SS, Ahmad M. Immobilization of lead in contaminated firing range soil using biochar. Environmental Science and Pollution Research.

[3] Al-Farraj AS, Usman ARA, Al Otaibi SHM. Assessment of heavy metals contamination in soils surrounding a gold mine: Comparison of two digestion methods. Chemistry and Ecology.

[4] Noman A, Aqeel M. miRNA-based heavy metal homeostasis and plant growth. Environmental Science and Pollution Research. 2017;**24**(11):3-10

[5] Pathak H. Trend of fertility status of Indian soils. Current Advances in Agricultural Sciences. 2010;**2**(1):10-12

[6] Hariprasad NV, Dayananda HS. Environmental impact due to agricultural runoff containing heavy metals—A review. International Journal of Scientific and Research Publications.

[7] Yargholi B, Azarneshan S. Longterm effects of pesticides and chemical fertilizers usage on some soil properties and accumulation of heavy metals in the soil (case study of Moghan plain's (Iran) irrigation and drainage network). International Journal of Agriculture and

Crop Sciences. 2014;**7**:518-523

[8] Prashar P, Shah S. Impact of fertilizers and pesticides on soil microflora in agriculture sustainable agriculture reviews. Sustainable Agriculture Reviews. 2016;**19**:331-362

[9] Wu F, Gai Y, Jiao Z, Liu Y, Ma X, An L, et al. The community structure of

2017;**214**(3):943-951

**References**

2013;**20**:8464-8471

2013;**29**:329-339

2013;**3**(5):1-6

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

#### **References**

*Biochar - An Imperative Amendment for Soil and the Environment*

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\* and Pankaj Sanwal<sup>2</sup>

1 Department of Biotechnology, Kumaun University, Bhimtal Campus, Nainital,

2 Biochemical Engineering Department, B.T. Kumaon Institute of Technology,

\*Address all correspondence to: saxenajyoti30@gmail.com

**12**

**Author details**

Dwarahat, India

Jyoti Rawat1

India

provided the original work is properly cited.

, Jyoti Saxena<sup>2</sup>

[1] Thalmann M, Santelia D. Starch as a determinant of plant fitness under abiotic stress. The New Phytologist. 2017;**214**(3):943-951

[2] Moon DH, Park JW, Chang YY, Ok YS, Lee SS, Ahmad M. Immobilization of lead in contaminated firing range soil using biochar. Environmental Science and Pollution Research. 2013;**20**:8464-8471

[3] Al-Farraj AS, Usman ARA, Al Otaibi SHM. Assessment of heavy metals contamination in soils surrounding a gold mine: Comparison of two digestion methods. Chemistry and Ecology. 2013;**29**:329-339

[4] Noman A, Aqeel M. miRNA-based heavy metal homeostasis and plant growth. Environmental Science and Pollution Research. 2017;**24**(11):3-10

[5] Pathak H. Trend of fertility status of Indian soils. Current Advances in Agricultural Sciences. 2010;**2**(1):10-12

[6] Hariprasad NV, Dayananda HS. Environmental impact due to agricultural runoff containing heavy metals—A review. International Journal of Scientific and Research Publications. 2013;**3**(5):1-6

[7] Yargholi B, Azarneshan S. Longterm effects of pesticides and chemical fertilizers usage on some soil properties and accumulation of heavy metals in the soil (case study of Moghan plain's (Iran) irrigation and drainage network). International Journal of Agriculture and Crop Sciences. 2014;**7**:518-523

[8] Prashar P, Shah S. Impact of fertilizers and pesticides on soil microflora in agriculture sustainable agriculture reviews. Sustainable Agriculture Reviews. 2016;**19**:331-362

[9] Wu F, Gai Y, Jiao Z, Liu Y, Ma X, An L, et al. The community structure of microbial in arable soil under different long-term fertilization regimes in the Loess Plateau of China. African Journal of Microbiology Research. 2012;**6**:6152-6164

[10] Paz-Ferreiro J, Lu H, Fu S, Méndez A, Gascó G. Use of phytoremediation and biochar to remediate heavy metal polluted soils: A review. Solid Earth Discussions. 2013;**5**:2155-2179

[11] Lahori AH, Zhanyu G, Zhang Z, li R, Mahar A, Awasthi M, et al. Use of biochar as an amendment for remediation of heavy metalcontaminated soils: Prospects and challenges. Pedosphere. 2017;**27**:991-1014

[12] García AC, de Souza LGA, Pereira MG, Castro RN, García-Mina JM, Zonta E, et al. Structure-property-function relationship in humic substances to explain the biological activity in plants. Scientific Reports. 2016;**6**:20798. DOI: 10.1038/srep20798

[13] Zhang R, Zhang Y, Song L, Song X, Hanninen H, Wu J. Biochar enhances nut quality of *Torreya grandis* and soil fertility under simulated nitrogen deposition. Forest Ecology and Management. 2017;**391**:321-329

[14] Debela F, Thring RW, Arocena JM. Immobilization of heavy metals by co-pyrolysis of contaminated soil with woody biomass. Water, Air, and Soil Pollution. 2012;**223**:1161-1170

[15] Bonanomi G, Ippolito F, Cesarano G, Nanni B, Lombardi N, Rita A, et al. Biochar as plant growth promoter: Better off alone or mixed with organic amendments? Frontiers in Plant Science. 2017;**8**:1570. DOI: 10.3389/ fpls.2017.01570

[16] Dume B, Mosissa T, Nebiyu A. Effect of biochar on soil properties and lead (Pb) availability in a military camp in South West Ethiopia. African Journal of Environmental Science and Technology. 2016;**10**(3):77-85

[17] Verheijen F, Jeffery S, Bastos AC, van der Velde M, Diafas I. Biochar Application to Soils—A Critical Scientific Review of Effects on Soil Properties, Processes and Functions. Luxemburg: EUR 24099 EN Office for the Official Publications of the European Communities; 2009. p. 149

[18] Nigussie A, Kissi E, Misganaw M, Ambaw G. Effect of biochar application on soil properties and nutrient uptake of Lettuces (*Lactuca sativa*) grown in chromium polluted soils. American-Eurasian Journal of Agriculture and Environmental Science. 2012;**12**(3):369-376

[19] Chan K, Van Zwieten L, Meszaros I, Downie A, Joseph S. Using poultry litter biochars as soil amendments. Australian Journal of Soil Research. 2008;**46**(5):437-444

[20] Saxena J, Rana G, Pandey M. Impact of addition of biochar along with *Bacillus* sp. on growth and yield of French beans. Scientia Horticulturae. 2013;**162**:351-356

[21] Placek A, Grobelak A, Kacprzak M. Improving the phytoremediation of heavy metals contaminated soil by use of sewage sludge. International Journal of Phytoremediation. 2016;**18**(6):605-618

[22] Ronsse F, van Hecke S, Dickinson D, Prins W. Production and characterization of slow pyrolysis biochar: Influence of feedstock type and pyrolysis conditions. GCB Bioenergy. 2013;**5**:104-115

[23] Kiran YK, Barkat A, Xiao-qiang CUI, Ying F, Feng-shan P, Lin T, et al. Cow manure and cow manure-derived biochar application as a soil amendment for reducing cadmium availability and accumulation by *Brassica chinensis* L. in acidic red soil. Journal of Integrative Agriculture. 2017;**16**(3):725-734

[24] Chan KY, Van Zwieten L, Meszaros I, Downie A, Joseph S. Agronomic values of greenwaste biochar as a soil amendment. Australian Journal of Soil Research. 2007;**45**:629-634

[25] Novotny EH, Maia CMB de F, Carvalho MT de M, Madari BE. Biochar: Pyrogenic carbon for agricultural use—A critical review. Revista Brasileira de Ciência do Solo. 2015;**39**(2):321-344

[26] Kameyama K, Miyamoto T, Iwata Y, Shiono T. Influences of feedstock and pyrolysis temperature on the nitrate adsorption of biochar. Soil Science and Plant Nutrition. 2016;**62**(2):180-184

[27] Woolf D, Amonette J, Street-Perrott F, Lehmann J, Joseph S. Sustainable biochar to mitigate global climate change. Nature Communications. 2010;**1**:1-9

[28] Tumuluru JS, Sokhansanj S, Hess JR, Wright CT, Boardman RD. A review on biomass torrefaction process and product properties for energy applications. Industrial Biotechnology. 2011;**7**:384-402

[29] Sohi S, Loez-Capel S, Krull E, Bol R. Biochar's roles in soil and climate change: A review of research needs. CSIRO Land and Water Science Report. 2009;**5**(09):17-31

[30] Reddy KR. Characteristics and applications of biochar for environmental remediation: A review. Critical Reviews in Environmental Science and Technology. 2015;**45**:939-969

[31] Peterson SC, Jackson MA, Kim S, Palmquist DE. Increasing biochar surface area: Optimization of ball milling parameters. Powder Technology. 2012;**228**:115-120

**15**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

Animal and Environmental Sciences.

Science, Engineering and Technology.

[42] Liang B, Lehmann J, Solomon D, Kinyangi J, Grossman J, O"Neill B, et al. Black carbon increases cation exchange capacity in soils. Soil Science Society of America Journal. 2006;**70**:1719-1730

[43] Lehmann J. Bio-energy in the black. Frontiers in Ecology and the Environment. 2007;**5**(7):381-387

[44] Blanco-Canqui H. Biochar and soil physical properties. Soil Science Society of America Journal. 2017;**81**:687-711

[45] Hammes K, Schmidt MWI. Changes

in biochar in soils. In: Lehmann M, Joseph S, editors. Biochar for Environmental Management Science and Technology. London: Earthscan;

[46] Lehmann J, Gaunt J, Rondon M. Biochar sequestration in the terrestrial ecosystem—A review.

Global Change. 2006;**11**:403-427

for Environmental Management: Science and Technology. 2nd ed. Routledge; 2015. pp. 421-454

[48] Cao Y, Gao Y, Qi Y, Li J. Biocharenhanced composts reduce the potential

leaching of nutrients and heavy metals and suppress plant-parasitic nematodes in excessively fertilized cucumber soils. Environmental Science and Pollution Research International.

2018;**25**(8):7589-7599

[47] DeLuca TH, Gundale MJ, MacKenzie MD, Jones DL. Biochar effects on soil nutrient transformation. In: Lehmann J, Joseph S, editors. Biochar

Mitigation and Adaptation Strategies for

2009. pp. 169-182

[41] Ajema L. Effects of biochar application on beneficial soil organism review. International Journal of Research Studies in

2012;**2**(1):197-201

2018;**5**(5):9-18

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

[32] Sullivan AL, Ball R. Thermal decomposition and combustion chemistry of cellulosic biomass. Atmospheric Environment.

[33] Zhu L, Lei H, Zhang Y, Zhang X, Bu Q, Wei Y, et al. A review of biochar derived from pyrolysis and its application in biofuel production. SF Journal of Material and Chemical

[34] Brown TR, Wright MM, Brown RC. Estimating profitability of two biochar production scenarios: Slow pyrolysis vs fast pyrolysis. Biofuels, Bioproducts and Biorefining.

[35] Joseph SD, Camps-Arbestain M, Lin Y, Munroe P, Chia CH, Hook J, et al. An investigation into the reactions of biochar in soil. Australian Journal of Soil

Research. 2010;**48**:501-515

2003;**42**(8):1619-1640

2011;**112**(2):159-166

[36] Antal MJ, Grønli M. The art, science, and technology of charcoal production. Industrial and Engineering Chemistry Research.

[37] Peng X, Ye LL, Wang CH, Bo S. Temperature and duration dependent rice straw derived biochar: Characteristics and its effects on soil properties of an Ultisol in southern China. Soil and Tillage Research.

[38] Dutta B. Assessment of pyrolysis techniques of lignocellulosic biomass for biochar production [dissertation master's thesis]. McGill University; 2010

[39] Stoyle A. Biochar production for carbon sequestration [master's thesis]. Shanghai Jiao Tong University; 2011

[40] Shenbagavalli S, Mahimairaja S. Production and characterization of biochar from different biological wastes. International Journal of Plant,

Engineering. 2018;**1**(1):1007

2012;**47**:133-141

2011;**5**(1):54-68

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

[32] Sullivan AL, Ball R. Thermal decomposition and combustion chemistry of cellulosic biomass. Atmospheric Environment. 2012;**47**:133-141

*Biochar - An Imperative Amendment for Soil and the Environment*

for reducing cadmium availability and accumulation by *Brassica chinensis* L. in acidic red soil. Journal of Integrative Agriculture. 2017;**16**(3):725-734

[24] Chan KY, Van Zwieten L, Meszaros I, Downie A, Joseph S. Agronomic values of greenwaste biochar as a soil amendment. Australian Journal of Soil

Research. 2007;**45**:629-634

[25] Novotny EH, Maia CMB de F, Carvalho MT de M, Madari BE. Biochar: Pyrogenic carbon for agricultural use—A critical review. Revista Brasileira de Ciência do Solo. 2015;**39**(2):321-344

[26] Kameyama K, Miyamoto T, Iwata Y, Shiono T. Influences of feedstock and pyrolysis temperature on the nitrate adsorption of biochar. Soil Science and Plant Nutrition. 2016;**62**(2):180-184

[27] Woolf D, Amonette J, Street-Perrott F, Lehmann J, Joseph S. Sustainable biochar to mitigate global climate change. Nature Communications.

[28] Tumuluru JS, Sokhansanj S, Hess JR, Wright CT, Boardman RD. A review on biomass torrefaction process and product properties for energy applications. Industrial Biotechnology.

[29] Sohi S, Loez-Capel S, Krull E, Bol R. Biochar's roles in soil and climate change: A review of research needs. CSIRO Land and Water Science Report.

Environmental Science and Technology.

[31] Peterson SC, Jackson MA, Kim S, Palmquist DE. Increasing biochar surface area: Optimization of ball milling parameters. Powder Technology.

[30] Reddy KR. Characteristics and applications of biochar for environmental remediation: A review. Critical Reviews in

2010;**1**:1-9

2011;**7**:384-402

2009;**5**(09):17-31

2015;**45**:939-969

2012;**228**:115-120

and lead (Pb) availability in a military camp in South West Ethiopia. African Journal of Environmental Science and

[17] Verheijen F, Jeffery S, Bastos AC, van der Velde M, Diafas I. Biochar Application to Soils—A Critical Scientific Review of Effects on Soil Properties, Processes and Functions. Luxemburg: EUR 24099 EN Office for the Official Publications of the European Communities; 2009. p. 149

[18] Nigussie A, Kissi E, Misganaw M, Ambaw G. Effect of biochar application on soil properties and nutrient uptake of Lettuces (*Lactuca sativa*) grown in chromium polluted soils. American-Eurasian Journal of Agriculture and Environmental Science.

[19] Chan K, Van Zwieten L, Meszaros I, Downie A, Joseph S. Using poultry litter biochars as soil amendments. Australian Journal of Soil Research.

[20] Saxena J, Rana G, Pandey M. Impact of addition of biochar along with *Bacillus* sp. on growth and yield of French beans. Scientia Horticulturae.

[21] Placek A, Grobelak A, Kacprzak M. Improving the phytoremediation of heavy metals contaminated soil by use of sewage sludge. International Journal of Phytoremediation.

[22] Ronsse F, van Hecke S, Dickinson

[23] Kiran YK, Barkat A, Xiao-qiang CUI, Ying F, Feng-shan P, Lin T, et al. Cow manure and cow manure-derived biochar application as a soil amendment

D, Prins W. Production and characterization of slow pyrolysis biochar: Influence of feedstock type and pyrolysis conditions. GCB Bioenergy.

2012;**12**(3):369-376

2008;**46**(5):437-444

2013;**162**:351-356

2016;**18**(6):605-618

2013;**5**:104-115

Technology. 2016;**10**(3):77-85

**14**

[33] Zhu L, Lei H, Zhang Y, Zhang X, Bu Q, Wei Y, et al. A review of biochar derived from pyrolysis and its application in biofuel production. SF Journal of Material and Chemical Engineering. 2018;**1**(1):1007

[34] Brown TR, Wright MM, Brown RC. Estimating profitability of two biochar production scenarios: Slow pyrolysis vs fast pyrolysis. Biofuels, Bioproducts and Biorefining. 2011;**5**(1):54-68

[35] Joseph SD, Camps-Arbestain M, Lin Y, Munroe P, Chia CH, Hook J, et al. An investigation into the reactions of biochar in soil. Australian Journal of Soil Research. 2010;**48**:501-515

[36] Antal MJ, Grønli M. The art, science, and technology of charcoal production. Industrial and Engineering Chemistry Research. 2003;**42**(8):1619-1640

[37] Peng X, Ye LL, Wang CH, Bo S. Temperature and duration dependent rice straw derived biochar: Characteristics and its effects on soil properties of an Ultisol in southern China. Soil and Tillage Research. 2011;**112**(2):159-166

[38] Dutta B. Assessment of pyrolysis techniques of lignocellulosic biomass for biochar production [dissertation master's thesis]. McGill University; 2010

[39] Stoyle A. Biochar production for carbon sequestration [master's thesis]. Shanghai Jiao Tong University; 2011

[40] Shenbagavalli S, Mahimairaja S. Production and characterization of biochar from different biological wastes. International Journal of Plant, Animal and Environmental Sciences. 2012;**2**(1):197-201

[41] Ajema L. Effects of biochar application on beneficial soil organism review. International Journal of Research Studies in Science, Engineering and Technology. 2018;**5**(5):9-18

[42] Liang B, Lehmann J, Solomon D, Kinyangi J, Grossman J, O"Neill B, et al. Black carbon increases cation exchange capacity in soils. Soil Science Society of America Journal. 2006;**70**:1719-1730

[43] Lehmann J. Bio-energy in the black. Frontiers in Ecology and the Environment. 2007;**5**(7):381-387

[44] Blanco-Canqui H. Biochar and soil physical properties. Soil Science Society of America Journal. 2017;**81**:687-711

[45] Hammes K, Schmidt MWI. Changes in biochar in soils. In: Lehmann M, Joseph S, editors. Biochar for Environmental Management Science and Technology. London: Earthscan; 2009. pp. 169-182

[46] Lehmann J, Gaunt J, Rondon M. Biochar sequestration in the terrestrial ecosystem—A review. Mitigation and Adaptation Strategies for Global Change. 2006;**11**:403-427

[47] DeLuca TH, Gundale MJ, MacKenzie MD, Jones DL. Biochar effects on soil nutrient transformation. In: Lehmann J, Joseph S, editors. Biochar for Environmental Management: Science and Technology. 2nd ed. Routledge; 2015. pp. 421-454

[48] Cao Y, Gao Y, Qi Y, Li J. Biocharenhanced composts reduce the potential leaching of nutrients and heavy metals and suppress plant-parasitic nematodes in excessively fertilized cucumber soils. Environmental Science and Pollution Research International. 2018;**25**(8):7589-7599

[49] Slapakova B, Jerabkova V, Tejnecky DO. The biochar effect on soil respiration and nitrification. Plant, Soil and Environment. 2018;**64**(3):114-119

[50] Saito M, Marumoto T. Inoculation with arbuscular mycorrhizal fungi: The status quo in Japan and the future prospects. Plant and Soil. 2002;**244**:273-279

[51] Skjemstad JO, Janik LJ, Taylor JA. Non-living soil organic matter: What do we know about it? Australian Journal of Experimental Agriculture. 1998;**38**:667-680

[52] Swift RS. Sequestration of carbon by soil. Soil Science. 2001;**166**:858-871

[53] Krull ES, Skjemstad J, Graetz D, Grice K, Dunning W, Cook G, et al. 13C-depleted charcoal from C4 grasses and the role of occluded carbon in phytoliths. Organic Geochemistry. 2003;**34**:1337-1352

[54] Hazarika BN, Ansari S. Biofertilizers in fruit crops—A review. Agricultural Reviews. 2007;**28**(1):69-74

[55] Beesley L, Moreno-Jiménez E, Gomez-Eyles JL, Harris E, Robinson B, Sizmur T. A review of biochars' potential role in the remediation, revegetation and restoration of contaminated soils. Environmental Pollution. 2011;**159**:3269-3282

[56] Mensah AK, Frimpong KA. Biochar and/or compost applications improve soil properties, growth, and yield of maize grown in acidic rainforest and coastal savannah soils in Ghana. International Journal of Agronomy. 2018:1-8. DOI: 10.1155/2018/6837404

[57] Glaser B, Lehmann J, Zech W. Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal: A review. Biology and Fertility of Soils. 2002;**35**:219-230

[58] Lehmann J, da Silva JP Jr, Steiner C, Nehls T, Zech W, Glaser B. Nutrient availability and leaching in an archaeological anthrosol and a ferrasol of the Central Amazon basin: Fertilizer, manure, and charcoal amendments. Plant and Soil. 2003;**249**:343-357

[59] Yuan J, Xu R, Zhang H. The forms of alkalis in the biochar produced from crop residues at different temperatures. Bioresource Technology. 2011;**102**:3488-3497

[60] Zhang A, Cui L, Pan G, Li L, Hussain Q , Zhang X, et al. Effect of biochar amendment on yield and methane and nitrous oxide emissions from a rice paddy from Tai Lake plain, China. Agriculture, Ecosystems and Environment. 2010;**139**(4):469-475

[61] Spokas KA, Koskinen WC, Baker JM, Reicosky DC. Impacts of woodchip biochar additions on greenhouse gas production and sorption/degradation of two herbicides in a minnesota soil. Chemosphere. 2009;**77**:574-581

[62] Bonanomi G, Ippolito F, Scala F. A "black" future for plant pathology? Biochar As a new soil amendment for controlling plant diseases. Journal of Plant Pathology. 2015;**97**(2):223-234

[63] Elmer W, White JC, Pignatello JJ. Impact of biochar addition to soil on the bioavailability of chemicals important in agriculture. Report. New Haven: University of Connecticut; 2010

[64] Thies JE, Rillig M. Characteristics of biochar: Biological properties. In: Lehmann M, Joseph S, editors. Biochar for Environmental Management Science and Technology. London: Earthscan; 2009. pp. 85-105

[65] Nerome M, Toyota K, Islam TM, Nishimima T, Matsuoka T, Sato K, et al. Suppression of bacterial wilt of tomato by incorporation of municipal biowaste

**17**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

[74] Saarnio S, Heimonen K, Kettunen R. Biochar addition indirectly affects N2O emissions via soil moisture and plant N uptake. Soil Biology and Biochemistry. 2013;**58**:99-106

[75] Rondon M, Lehmann J, Ramírez J, Hurtado M. Biological nitrogen fixation by common beans (*Phaseolus vulgaris* L.) increases with bio-char additions. Biology and Fertility of Soils.

[76] Gaskin JW, Speir RA, Harris K, Das KC, Lee RD, Morris LA, et al. Effect of peanut hull and pine chip biochar on soil nutrients, corn nutrient status, and yield. Agronomy Journal.

[77] Nartey OD, Zhao B. Biochar preparation, characterization, and adsorptive capacity and its effect on bioavailability of contaminants: An overview. Advances in Materials Science and Engineering. 2014;**2014**(715398). p. 12. Available from: http://dx.doi.

org/10.1155/2014/715398

[79] Saxena J, Rawat J, Sanwal P. Enhancement of growth and yield of *glycine max* plants with inoculation of phosphate solubilizing fungus *Aspergillus niger* K7 and biochar amendment in soil. Communications in Soil Science and Plant Analysis.

2016;**47**(20):2334-2347

[80] Saxena J, Rawat J, Kumar R. Conversion of biomass waste into biochar and the effect on mung bean crop production. Clean—Soil, Air, Water. 2017;**45**(7):1501020 (1-9)

[81] Solaiman ZM, Blackwell P, Abbott LK, Storer P. Direct and residual effect of biochar application on mycorrhizal

[78] Busscher WJ, Novak JM, Evans DE, Watts DW, Niandou MAS, Ahmedna M. Influence of pecan biochar on physical properties of a Norfolk loamy sand. Soil Science. 2010;**175**:10-14

2007;**43**:699-708

2010;**102**:623-633

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

charcoal into soil. Soil Microorganisms.

agriculture in Japan. Keynote address, 1st Asia Pacific Biochar Conference, May 17-20, 2009, Gold Coast, Australia

[67] van Zwieten L, Kimber S, Downie A, Morris S, Petty S, Rust J, et al. A glasshouse study on the interaction of low mineral ash biochar with nitrogen in a sandy soil. Australian Journal of Soil

[66] Ogawa M. Charcoal use in

Research. 2010;**48**:569-576

2009;**76**:665-671

2009;**16**:1-9

2010;**39**:1224-1235

2013;**370**(1-2):527-540

and Soil. 2012;**350**:57-69

[68] Yu XY, Ying GG, Kookana RS. Reduced plant uptake of pesticides with biochar additions to soil. Chemosphere.

[69] Hua L, Wu WX, Liu YX, McBride M, Chen YX. Reduction of nitrogen loss and Cu and Zn mobility during sludge composting with bamboo charcoal amendment. Environmental Science and Pollution Research International.

[70] Major J, Lehmann J, Rondon M, Goodale C. Fate of soil-applied black carbon: Downward migration, leaching and soil respiration. Global Change Biology. 2010;**16**(4):1366-1379

[71] Singh PB, Hatton JB, Singh B, Cowie LA, Kathuria A. Influence of biochars on nitrous oxide emission and nitrogen leaching from two contrasting soils. Journal of Environmental Quality.

[72] Xie Z, Xu Y, Liu G, Liu Q , Zhu J, Tu C, et al. Impact of biochar application on nitrogen nutrition of rice, greenhouse-gas emissions and soil organic carbon dynamics in two paddy soils of China. Plant and Soil.

[73] Taghizadeh-Toosi A, Clough TJ, Sherlock RR, Condron LM. Biochar adsorbed ammonia is bioavailable. Plant

2005;**59**(1):9-14

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

charcoal into soil. Soil Microorganisms. 2005;**59**(1):9-14

*Biochar - An Imperative Amendment for Soil and the Environment*

[58] Lehmann J, da Silva JP Jr, Steiner C, Nehls T, Zech W, Glaser B. Nutrient availability and leaching in an archaeological anthrosol and a ferrasol of the Central Amazon basin: Fertilizer, manure, and

2003;**249**:343-357

2011;**102**:3488-3497

charcoal amendments. Plant and Soil.

[59] Yuan J, Xu R, Zhang H. The forms of alkalis in the biochar produced from crop residues at different

temperatures. Bioresource Technology.

[60] Zhang A, Cui L, Pan G, Li L, Hussain Q , Zhang X, et al. Effect of biochar amendment on yield and methane and nitrous oxide emissions from a rice paddy from Tai Lake plain, China. Agriculture, Ecosystems and Environment. 2010;**139**(4):469-475

[61] Spokas KA, Koskinen WC, Baker JM, Reicosky DC. Impacts of woodchip biochar additions on greenhouse gas production and sorption/degradation of two herbicides in a minnesota soil. Chemosphere. 2009;**77**:574-581

[62] Bonanomi G, Ippolito F, Scala F. A "black" future for plant pathology? Biochar As a new soil amendment for controlling plant diseases. Journal of Plant Pathology. 2015;**97**(2):223-234

[63] Elmer W, White JC, Pignatello JJ. Impact of biochar addition to soil on the bioavailability of chemicals important in agriculture. Report. New Haven: University of Connecticut; 2010

[64] Thies JE, Rillig M. Characteristics of biochar: Biological properties. In: Lehmann M, Joseph S, editors. Biochar for Environmental Management Science and Technology. London: Earthscan;

[65] Nerome M, Toyota K, Islam TM, Nishimima T, Matsuoka T, Sato K, et al. Suppression of bacterial wilt of tomato by incorporation of municipal biowaste

2009. pp. 85-105

[49] Slapakova B, Jerabkova V, Tejnecky

respiration and nitrification. Plant, Soil and Environment. 2018;**64**(3):114-119

[50] Saito M, Marumoto T. Inoculation with arbuscular mycorrhizal fungi: The status quo in Japan and the future prospects. Plant and Soil.

[51] Skjemstad JO, Janik LJ, Taylor JA. Non-living soil organic matter: What do we know about it? Australian Journal of Experimental Agriculture.

[52] Swift RS. Sequestration of carbon by soil. Soil Science. 2001;**166**:858-871

[54] Hazarika BN, Ansari S. Biofertilizers in fruit crops—A review. Agricultural

[56] Mensah AK, Frimpong KA. Biochar and/or compost applications improve soil properties, growth, and yield of maize grown in acidic rainforest and coastal savannah soils in Ghana. International Journal of Agronomy. 2018:1-8. DOI: 10.1155/2018/6837404

[57] Glaser B, Lehmann J, Zech W. Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal: A review. Biology and Fertility of Soils.

[53] Krull ES, Skjemstad J, Graetz D, Grice K, Dunning W, Cook G, et al. 13C-depleted charcoal from C4 grasses and the role of occluded carbon in phytoliths. Organic Geochemistry.

DO. The biochar effect on soil

2002;**244**:273-279

1998;**38**:667-680

2003;**34**:1337-1352

Reviews. 2007;**28**(1):69-74

[55] Beesley L, Moreno-Jiménez E, Gomez-Eyles JL, Harris E, Robinson B, Sizmur T. A review of biochars' potential role in the remediation, revegetation and restoration of contaminated soils. Environmental Pollution. 2011;**159**:3269-3282

**16**

2002;**35**:219-230

[66] Ogawa M. Charcoal use in agriculture in Japan. Keynote address, 1st Asia Pacific Biochar Conference, May 17-20, 2009, Gold Coast, Australia

[67] van Zwieten L, Kimber S, Downie A, Morris S, Petty S, Rust J, et al. A glasshouse study on the interaction of low mineral ash biochar with nitrogen in a sandy soil. Australian Journal of Soil Research. 2010;**48**:569-576

[68] Yu XY, Ying GG, Kookana RS. Reduced plant uptake of pesticides with biochar additions to soil. Chemosphere. 2009;**76**:665-671

[69] Hua L, Wu WX, Liu YX, McBride M, Chen YX. Reduction of nitrogen loss and Cu and Zn mobility during sludge composting with bamboo charcoal amendment. Environmental Science and Pollution Research International. 2009;**16**:1-9

[70] Major J, Lehmann J, Rondon M, Goodale C. Fate of soil-applied black carbon: Downward migration, leaching and soil respiration. Global Change Biology. 2010;**16**(4):1366-1379

[71] Singh PB, Hatton JB, Singh B, Cowie LA, Kathuria A. Influence of biochars on nitrous oxide emission and nitrogen leaching from two contrasting soils. Journal of Environmental Quality. 2010;**39**:1224-1235

[72] Xie Z, Xu Y, Liu G, Liu Q , Zhu J, Tu C, et al. Impact of biochar application on nitrogen nutrition of rice, greenhouse-gas emissions and soil organic carbon dynamics in two paddy soils of China. Plant and Soil. 2013;**370**(1-2):527-540

[73] Taghizadeh-Toosi A, Clough TJ, Sherlock RR, Condron LM. Biochar adsorbed ammonia is bioavailable. Plant and Soil. 2012;**350**:57-69

[74] Saarnio S, Heimonen K, Kettunen R. Biochar addition indirectly affects N2O emissions via soil moisture and plant N uptake. Soil Biology and Biochemistry. 2013;**58**:99-106

[75] Rondon M, Lehmann J, Ramírez J, Hurtado M. Biological nitrogen fixation by common beans (*Phaseolus vulgaris* L.) increases with bio-char additions. Biology and Fertility of Soils. 2007;**43**:699-708

[76] Gaskin JW, Speir RA, Harris K, Das KC, Lee RD, Morris LA, et al. Effect of peanut hull and pine chip biochar on soil nutrients, corn nutrient status, and yield. Agronomy Journal. 2010;**102**:623-633

[77] Nartey OD, Zhao B. Biochar preparation, characterization, and adsorptive capacity and its effect on bioavailability of contaminants: An overview. Advances in Materials Science and Engineering. 2014;**2014**(715398). p. 12. Available from: http://dx.doi. org/10.1155/2014/715398

[78] Busscher WJ, Novak JM, Evans DE, Watts DW, Niandou MAS, Ahmedna M. Influence of pecan biochar on physical properties of a Norfolk loamy sand. Soil Science. 2010;**175**:10-14

[79] Saxena J, Rawat J, Sanwal P. Enhancement of growth and yield of *glycine max* plants with inoculation of phosphate solubilizing fungus *Aspergillus niger* K7 and biochar amendment in soil. Communications in Soil Science and Plant Analysis. 2016;**47**(20):2334-2347

[80] Saxena J, Rawat J, Kumar R. Conversion of biomass waste into biochar and the effect on mung bean crop production. Clean—Soil, Air, Water. 2017;**45**(7):1501020 (1-9)

[81] Solaiman ZM, Blackwell P, Abbott LK, Storer P. Direct and residual effect of biochar application on mycorrhizal

root colonisation, growth and nutrition of wheat. Australian Journal of Soil Research. 2010;**48**:546-554

[82] Warnock DD, Lehmann J, Kuyper TW, Rillig MC. Mycorrhizal responses to biochar in soil—Concepts and mechanisms. Plant and Soil. 2007;**300**:9-20

[83] Rondon M, Ramirez A, Hurtado M. Charcoal Additions to High Fertility Ditches Enhance Yields and Qvuality of Cash Crops in Andean Hillsides of Columbia (CIAT Annual Report 2004). Cali, Colombia; 2004

[84] Schwartz MW, Hoeksema JD, Gehring CA, Johnson NC, Klironomos JN, Abbott LK, et al. The promise and the potential consequences of the global transport of mycorrhizal fungal inoculum. Ecology Letters. 2006;**9**:501-515

[85] Saito M. Charcoal as a micro habitat for VA mycorrhizal fungi, and its practical application. Agriculture, Ecosystems and Environment. 1990;**29**:341-344

[86] Pietikainen J, Kiikkila O, Fritze H. Charcoal as a habitat for microbes and its effect on the microbial community of the underlying humus. Oikos. 2000;**89**:231-242

[87] Ezawa T, Yamamoto K, Yoshida S. Enhancement of the effectiveness of indigenous arbuscular mycorrhizal fungi by inorganic soil amendments. Soil Science and Plant Nutrition. 2002;**48**:897-900

[88] Major J, Steiner C, Ditommaso A, Falcão NP, Lehmann J. Weed composition and cover after three years of soil fertility management in the central Brazilian Amazon: Compost, fertilizer, manure and charcoal applications. Weed Biology and Management. 2005;**5**:69-76

[89] Oguntunde PG, Fosu M, Ajayi AE, van de Giesen N. Effects of charcoal production on maize yield, chemical properties and texture of soil. Biology and Fertility of Soils. 2004;**39**:295-299

[90] Major J, Rondon M, Molina D, Riha SJ, Lehmann J. Maize yield and nutrition during four years after biochar application to a Colombian savanna oxisol. Plant and Soil. 2010;**333**:117-128

[91] Asai H, Samson BK, Stephan HM, Songyikhangsuthor K, Homma K, Kiyono Y, et al. Biochar amendment techniques for upland rice production in Northern Laos: 1. Soil physical properties, leaf SPAD and grain yield. Field Crops Research. 2009;**111**(1-2):81-84

[92] Silber A, Levkovitch I, Graber ER. pH-dependent mineral release and surface properties of cornstraw biochar: Agronomic implications. Environmental Science and Technology. 2010;**44**:9318-9323

[93] Mikan CJ, Abrams MD. Altered forest composition and soil properties of historic charcoal hearths in southeastern Pennsylvania. Canadian Journal of Forest Research. 1995;**25**:687-696

[94] Matsubara Y, Hasegawa N, Fukui H. Incidence of *Fusarium* root rot in asparagus seedlings infected with arbuscular mycorrhizal fungus as affected by several soil amendments. Journal of the Japanese Society For Horticultural Science. 2002;**71**:370-374

[95] Elmer WH, Pignatello JJ. Effect of biochar amendments on mycorrhizal associations and *Fusarium* crown and root rot of asparagus in replant soils. Plant Disease. 2011;**95**:960-966

[96] Novak JM, Lima I, Gaskin JW, Steiner C, Das KC, Ahmedna M, et al. Characterization of designer biochar produced at different temperatures and their effects on a loamy sand. Annals of Environmental Science. 2009;**3**:195-206

**19**

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties*

*DOI: http://dx.doi.org/10.5772/intechopen.82151*

[97] Kammann C, Glaser B, Schmidt HP. Combining biochar and organic amendments. In: Shackley S, Ruysschaert G, Zwart K, Glaser B, editors. Biochar in European Soils and Agriculture: Science and Practice. New York: Routledge; 2016. pp. 136-164

[98] Liu J, Schulz H, Brandl S, Miehtke H, Huwe B, Glaser B. Short-term effect of biochar and compost on soil fertility and water status of a Dystric Cambisol in NE Germany under field conditions. Journal of Plant Nutrition and Soil

Science. 2012;**175**(5):1-10

[99] Yanai Y, Toyota K, Okazaki M. Effects of charcoal addition on N2O emissions from soil resulting from rewetting air-dried soil in short-term laboratory experiments. Soil Science and Plant Nutrition. 2007;**53**:181-188

[100] Spokas KA, Reikosky DC. Impacts of sixteen different biochars on soil greenhouse gas production. Annals of Environmental Science. 2009;**3**:179-193

*Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties DOI: http://dx.doi.org/10.5772/intechopen.82151*

[97] Kammann C, Glaser B, Schmidt HP. Combining biochar and organic amendments. In: Shackley S, Ruysschaert G, Zwart K, Glaser B, editors. Biochar in European Soils and Agriculture: Science and Practice. New York: Routledge; 2016. pp. 136-164

*Biochar - An Imperative Amendment for Soil and the Environment*

[89] Oguntunde PG, Fosu M, Ajayi AE, van de Giesen N. Effects of charcoal production on maize yield, chemical properties and texture of soil. Biology and Fertility of Soils. 2004;**39**:295-299

[90] Major J, Rondon M, Molina D, Riha SJ, Lehmann J. Maize yield and nutrition during four years after biochar application to a Colombian savanna oxisol. Plant and Soil. 2010;**333**:117-128

[91] Asai H, Samson BK, Stephan HM, Songyikhangsuthor K, Homma K, Kiyono Y, et al. Biochar amendment techniques for upland rice production in Northern Laos: 1. Soil physical properties, leaf SPAD and grain yield. Field Crops Research.

[92] Silber A, Levkovitch I, Graber ER. pH-dependent mineral release and surface properties of cornstraw biochar: Agronomic implications. Environmental Science and Technology.

[93] Mikan CJ, Abrams MD. Altered forest composition and soil properties of historic charcoal hearths in southeastern Pennsylvania. Canadian Journal of Forest Research. 1995;**25**:687-696

[94] Matsubara Y, Hasegawa N, Fukui H. Incidence of *Fusarium* root rot in asparagus seedlings infected with arbuscular mycorrhizal fungus as affected by several soil amendments. Journal of the Japanese Society For Horticultural Science. 2002;**71**:370-374

[95] Elmer WH, Pignatello JJ. Effect of biochar amendments on mycorrhizal associations and *Fusarium* crown and root rot of asparagus in replant soils. Plant Disease. 2011;**95**:960-966

[96] Novak JM, Lima I, Gaskin JW, Steiner C, Das KC, Ahmedna M, et al. Characterization of designer biochar produced at different temperatures and their effects on a loamy sand. Annals of Environmental Science. 2009;**3**:195-206

2009;**111**(1-2):81-84

2010;**44**:9318-9323

root colonisation, growth and nutrition of wheat. Australian Journal of Soil

Research. 2010;**48**:546-554

2007;**300**:9-20

Cali, Colombia; 2004

2006;**9**:501-515

1990;**29**:341-344

Oikos. 2000;**89**:231-242

2002;**48**:897-900

[82] Warnock DD, Lehmann J, Kuyper TW, Rillig MC. Mycorrhizal responses to biochar in soil—Concepts and mechanisms. Plant and Soil.

[83] Rondon M, Ramirez A, Hurtado M. Charcoal Additions to High Fertility Ditches Enhance Yields and Qvuality of Cash Crops in Andean Hillsides of Columbia (CIAT Annual Report 2004).

[84] Schwartz MW, Hoeksema JD, Gehring CA, Johnson NC, Klironomos JN, Abbott LK, et al. The promise and the potential consequences of the global transport of mycorrhizal fungal inoculum. Ecology Letters.

[85] Saito M. Charcoal as a micro habitat for VA mycorrhizal fungi, and its practical application. Agriculture, Ecosystems and Environment.

[86] Pietikainen J, Kiikkila O, Fritze H. Charcoal as a habitat for microbes and its effect on the microbial

community of the underlying humus.

[87] Ezawa T, Yamamoto K, Yoshida S. Enhancement of the effectiveness of indigenous arbuscular mycorrhizal fungi by inorganic soil amendments. Soil Science and Plant Nutrition.

[88] Major J, Steiner C, Ditommaso A, Falcão NP, Lehmann J. Weed composition and cover after three years of soil fertility management in the central Brazilian Amazon: Compost, fertilizer, manure and

charcoal applications. Weed Biology and

Management. 2005;**5**:69-76

**18**

[98] Liu J, Schulz H, Brandl S, Miehtke H, Huwe B, Glaser B. Short-term effect of biochar and compost on soil fertility and water status of a Dystric Cambisol in NE Germany under field conditions. Journal of Plant Nutrition and Soil Science. 2012;**175**(5):1-10

[99] Yanai Y, Toyota K, Okazaki M. Effects of charcoal addition on N2O emissions from soil resulting from rewetting air-dried soil in short-term laboratory experiments. Soil Science and Plant Nutrition. 2007;**53**:181-188

[100] Spokas KA, Reikosky DC. Impacts of sixteen different biochars on soil greenhouse gas production. Annals of Environmental Science. 2009;**3**:179-193

**21**

**Chapter 2**

**Abstract**

*Kayode S. Are*

Biochar and Soil Physical Health

The use of organic materials for reclamation of soil physical health indicators of degraded soil is germane for sustainable agriculture. Despite the soil conservation effectiveness of organic fertilizer*,* its adoption remains low among smallholder farmers in most parts of sub-Saharan Africa because of its offensive odor and bulkiness. Farmers desire materials that are not bulky, handled with ease, ensure maximum nutrient retention, improve soil structural quality, reduce soil compaction, and increase water retention, which will also increase soil productivity and crop yield. These are the greatest attractions for the introduction of biochar for improvement of soil physical health. The pyrolytic processes of various organic materials to biochar have suppressed the effects of distractive odor of fresh and composted organic materials while reducing the bulkiness experienced during application. The potentials of biochar in improving nutrient retention and release have been published by various authors, but little information is available for soil physical health indicators. Therefore, the potentials of biochar in restoring physical health indicators such as particle size distribution, bulk density, pore size distribution, soil water retention and distribution, compaction and aggregate size distribution and stability

of degraded soil shall be discussed in this chapter.

sustainable agriculture

**1. Introduction**

**Keywords:** degraded soil, biochar, physical health indicator, soil productivity,

Soil physical health is the ability of a given soil to meet plant and ecosystem requirements for water, aeration, and strength over time and to resist and recover from processes that might diminish that ability [1]. Application of organic materials for soil amendment, especially the composted manures, plays important roles in reclaiming and improving the physical health of degraded soils [2]. They have profound influence on almost all soil properties—such as structure (and hence on water infiltration and storage, susceptibility to surface runoff and erosion), cation exchange capacity, nutrient availability, buffering (pH, nutrient availability), color, and plant pest pressure. In spite of these potentials, their adoption as soil amendment remains low among smallholder farmers in most parts of sub-Saharan Africa because of their offensive odor and bulkiness. However, one of the greatest attractions for the use of biochar is the suppression of the effects of distractive odor of fresh and composted organic materials through pyrolytic processes, while the bulkiness experienced during application of composted manure is reduced. Biochar is a carbon-rich organic matter, which is generally derived from the incomplete combustion of waste biomass, and it is produced by the slow thermochemical pyrolysis of biomass materials. Organic wastes, such as livestock manures,

## **Chapter 2** Biochar and Soil Physical Health

*Kayode S. Are*

### **Abstract**

The use of organic materials for reclamation of soil physical health indicators of degraded soil is germane for sustainable agriculture. Despite the soil conservation effectiveness of organic fertilizer*,* its adoption remains low among smallholder farmers in most parts of sub-Saharan Africa because of its offensive odor and bulkiness. Farmers desire materials that are not bulky, handled with ease, ensure maximum nutrient retention, improve soil structural quality, reduce soil compaction, and increase water retention, which will also increase soil productivity and crop yield. These are the greatest attractions for the introduction of biochar for improvement of soil physical health. The pyrolytic processes of various organic materials to biochar have suppressed the effects of distractive odor of fresh and composted organic materials while reducing the bulkiness experienced during application. The potentials of biochar in improving nutrient retention and release have been published by various authors, but little information is available for soil physical health indicators. Therefore, the potentials of biochar in restoring physical health indicators such as particle size distribution, bulk density, pore size distribution, soil water retention and distribution, compaction and aggregate size distribution and stability of degraded soil shall be discussed in this chapter.

**Keywords:** degraded soil, biochar, physical health indicator, soil productivity, sustainable agriculture

#### **1. Introduction**

Soil physical health is the ability of a given soil to meet plant and ecosystem requirements for water, aeration, and strength over time and to resist and recover from processes that might diminish that ability [1]. Application of organic materials for soil amendment, especially the composted manures, plays important roles in reclaiming and improving the physical health of degraded soils [2]. They have profound influence on almost all soil properties—such as structure (and hence on water infiltration and storage, susceptibility to surface runoff and erosion), cation exchange capacity, nutrient availability, buffering (pH, nutrient availability), color, and plant pest pressure. In spite of these potentials, their adoption as soil amendment remains low among smallholder farmers in most parts of sub-Saharan Africa because of their offensive odor and bulkiness. However, one of the greatest attractions for the use of biochar is the suppression of the effects of distractive odor of fresh and composted organic materials through pyrolytic processes, while the bulkiness experienced during application of composted manure is reduced.

Biochar is a carbon-rich organic matter, which is generally derived from the incomplete combustion of waste biomass, and it is produced by the slow thermochemical pyrolysis of biomass materials. Organic wastes, such as livestock manures, sewage sludge, crop residues, and composts are converted to biochars and then applied to soils as an amendment. Biochar application as soil amendment improves crop productivity, enhances soil properties, and increases carbon storage in the soil due to its highly recalcitrant carbon content [3]. This practice has, however, received a growing interest as a sustainable process to improve the properties of highly degraded tropical soils [4, 5]. Biochars are characteristically very light materials with a high porosity and surface area, which alter some soil physical properties such as the bulk density (BD), water-holding capacity (WHC), surface area, and penetration resistance (PR) [6]. In Nigeria, when comparing the potential of poultry biochar with composted and noncomposted poultry litter, Are et al. [2] recorded an increase in soil water retention of between 3.3 and 31.3% following application of poultry litter biochar than uncharred poultry manures at lower water suction. Elsewhere, Major et al. [7] reported that the surface soils of oxisols amended with char at 20 Mg ha<sup>−</sup><sup>1</sup> contained more water by volume, and the water was held more tightly than unamended soils. In China, Chen [8] reported a decrease in bulk density by 4.5 and 6% with addition of 2.25 and 4.50 Mg ha<sup>−</sup><sup>1</sup> , respectively, while an increase in water holding capacity from 25 to 36% was recorded by Kinney [9] with 7% biochar by weight addition.

In spite of the benefits of biochar on soil physical properties reported by different authors [2, 6–9], most positive effects of biochar are seen with coarse- or medium-textured soils, suggesting improvement of water holding capacity (WHC) by biochar addition [10] but not with fine-textured soils. Research has shown that unfavorable soil physical changes sometimes occur when biochar is added as soil amendment. Soil aggregation, for instance, may not be immediately enhanced by biochar addition [6]. The application of oak-650 biochar (0.5%, w/w) by Mukherjee and Lal [11] on a degraded silty clay loam soil reduced aggregation by 10% relative to the control. Mukherjee [11] suggested that (i) there may be a threshold application rate below which no aggregate stability is achieved, and/or (ii) a higher interaction time is required. On the other hand, Tryon [12] reported that application of pine (Pinus spp.) and oak (Quercus spp.) biochars increased available water content (AWC) in a sandy soil, while having no effect in a loamy soil, and it decreased moisture content in a clayey soil, indicating that the effect of biochar on AWC can be strongly influenced by the soil textural classes. Similarly, Masiello et al. [13] reported that a high rate (up to 11.3 Mg ha<sup>−</sup><sup>1</sup> ) of maize stover biochar pyrolyzed at 350 and 550°C did not improve AWC in amended silt loam soils after incubation for 295 days, which was attributed to clogging of micropores by ash over time. The contrasting behaviors of biochars have been attributed by various researchers to biochar's particle size, shape, and internal structure, which alter pore characteristics and consequently influence soil water storage. With these contrasting trends (both positive and negative) of future biochar, future studies, especially at field scale with similar soil types with different biochar combinations over time, may shed light on this aspect. This chapter will discuss the practical use of biochar as it relates to the overall soil physical health.

#### **2. Physical properties of biochar**

Biochar is difficult to classify based on its properties, both chemical and physical, because of the variability imparted to it by the production conditions (time, temperature) and feedstock. Biochars (**Figure 1**) are of different particle sizes and do not have the same properties since their characteristics are controlled by many factors. Operating factors during the pyrolysis process that influence the resultant physical properties of biochar of any given biomass feedstock include heating rate, highest treatment temperature, pressure, reaction residence time, reaction vessel (orientation,

**23**

ing particles [15, 16].

**Figure 1.**

microstructural rearrangement.

*Biochars from feedstocks with different particle sizes.*

*Biochar and Soil Physical Health*

*DOI: http://dx.doi.org/10.5772/intechopen.83706*

dimensions, stirring regime, catalysts, etc.), pretreatment (drying, comminution, chemical activation, etc.), the flow rate of ancillary inputs (e.g., nitrogen, carbon dioxide, air, steam, etc.), and posttreatment (crushing, sieving, activation, etc.). Although all of these parameters contribute to the final biochar structure, the pyrolysis highest treatment temperature has been identified by Downie et al. [14] as the most important of the factors since the fundamental physical changes (i.e., the release of volatiles, the formation of intermediate melts, and the volatilization of the intermediate melts) are all temperature dependent. The temperature ranges, however, under which these stages occur, vary with feedstock. Heating rates and pressures are expected to have the second greatest influence since they affect the physical mass transfer of volatiles evolving at the given temperature from the react-

An additional mechanism producing the structural complexity of biochars is the occurrence of cracking. Biochar is typically laced with macrocracks, which can be related to both feedstock properties and the rate at which carbonization is carried out [17]. Wood biochar is generally broken and cracked due to shrinkage stresses developed because the surface of the material decomposes faster than its interior. Brown et al. [18] concluded that high-temperature (1000°C) surface area is controlled primarily by low-temperature (<450°C) cracking and high-temperature

The physical characteristics can be both directly and indirectly related to the way in which they affect soil systems. The physical characteristics of biochar depend not only upon the starting organic material (biomass), but also upon the carbonization

*Biochar - An Imperative Amendment for Soil and the Environment*

et al. [13] reported that a high rate (up to 11.3 Mg ha<sup>−</sup><sup>1</sup>

as it relates to the overall soil physical health.

**2. Physical properties of biochar**

tion of 2.25 and 4.50 Mg ha<sup>−</sup><sup>1</sup>

sewage sludge, crop residues, and composts are converted to biochars and then applied to soils as an amendment. Biochar application as soil amendment improves crop productivity, enhances soil properties, and increases carbon storage in the soil due to its highly recalcitrant carbon content [3]. This practice has, however, received a growing interest as a sustainable process to improve the properties of highly degraded tropical soils [4, 5]. Biochars are characteristically very light materials with a high porosity and surface area, which alter some soil physical properties such as the bulk density (BD), water-holding capacity (WHC), surface area, and penetration resistance (PR) [6]. In Nigeria, when comparing the potential of poultry biochar with composted and noncomposted poultry litter, Are et al. [2] recorded an increase in soil water retention of between 3.3 and 31.3% following application of poultry litter biochar than uncharred poultry manures at lower water suction. Elsewhere, Major et al. [7] reported that the surface soils of oxisols amended with char at 20 Mg ha<sup>−</sup><sup>1</sup>

tained more water by volume, and the water was held more tightly than unamended soils. In China, Chen [8] reported a decrease in bulk density by 4.5 and 6% with addi-

pyrolyzed at 350 and 550°C did not improve AWC in amended silt loam soils after incubation for 295 days, which was attributed to clogging of micropores by ash over time. The contrasting behaviors of biochars have been attributed by various researchers to biochar's particle size, shape, and internal structure, which alter pore characteristics and consequently influence soil water storage. With these contrasting trends (both positive and negative) of future biochar, future studies, especially at field scale with similar soil types with different biochar combinations over time, may shed light on this aspect. This chapter will discuss the practical use of biochar

Biochar is difficult to classify based on its properties, both chemical and physical, because of the variability imparted to it by the production conditions (time, temperature) and feedstock. Biochars (**Figure 1**) are of different particle sizes and do not have the same properties since their characteristics are controlled by many factors. Operating factors during the pyrolysis process that influence the resultant physical properties of biochar of any given biomass feedstock include heating rate, highest treatment temperature, pressure, reaction residence time, reaction vessel (orientation,

from 25 to 36% was recorded by Kinney [9] with 7% biochar by weight addition. In spite of the benefits of biochar on soil physical properties reported by different authors [2, 6–9], most positive effects of biochar are seen with coarse- or medium-textured soils, suggesting improvement of water holding capacity (WHC) by biochar addition [10] but not with fine-textured soils. Research has shown that unfavorable soil physical changes sometimes occur when biochar is added as soil amendment. Soil aggregation, for instance, may not be immediately enhanced by biochar addition [6]. The application of oak-650 biochar (0.5%, w/w) by Mukherjee and Lal [11] on a degraded silty clay loam soil reduced aggregation by 10% relative to the control. Mukherjee [11] suggested that (i) there may be a threshold application rate below which no aggregate stability is achieved, and/or (ii) a higher interaction time is required. On the other hand, Tryon [12] reported that application of pine (Pinus spp.) and oak (Quercus spp.) biochars increased available water content (AWC) in a sandy soil, while having no effect in a loamy soil, and it decreased moisture content in a clayey soil, indicating that the effect of biochar on AWC can be strongly influenced by the soil textural classes. Similarly, Masiello

, respectively, while an increase in water holding capacity

) of maize stover biochar

con-

**22**

**Figure 1.** *Biochars from feedstocks with different particle sizes.*

dimensions, stirring regime, catalysts, etc.), pretreatment (drying, comminution, chemical activation, etc.), the flow rate of ancillary inputs (e.g., nitrogen, carbon dioxide, air, steam, etc.), and posttreatment (crushing, sieving, activation, etc.).

Although all of these parameters contribute to the final biochar structure, the pyrolysis highest treatment temperature has been identified by Downie et al. [14] as the most important of the factors since the fundamental physical changes (i.e., the release of volatiles, the formation of intermediate melts, and the volatilization of the intermediate melts) are all temperature dependent. The temperature ranges, however, under which these stages occur, vary with feedstock. Heating rates and pressures are expected to have the second greatest influence since they affect the physical mass transfer of volatiles evolving at the given temperature from the reacting particles [15, 16].

An additional mechanism producing the structural complexity of biochars is the occurrence of cracking. Biochar is typically laced with macrocracks, which can be related to both feedstock properties and the rate at which carbonization is carried out [17]. Wood biochar is generally broken and cracked due to shrinkage stresses developed because the surface of the material decomposes faster than its interior. Brown et al. [18] concluded that high-temperature (1000°C) surface area is controlled primarily by low-temperature (<450°C) cracking and high-temperature microstructural rearrangement.

The physical characteristics can be both directly and indirectly related to the way in which they affect soil systems. The physical characteristics of biochar depend not only upon the starting organic material (biomass), but also upon the carbonization

or pyrolysis system by which they are made (including the pre- and posthandling of the biomass and biochar) [14].

The fundamental molecular structure of biochar creates both its surface area and porosity. However, pyrolysis processing of biomass enlarges the crystallites and makes them more ordered. This effect increases with highest treatment temperature. Lua et al. [15] demonstrated that increasing the pyrolysis temperature from 250 to 500°C increases the Brunauer, Emmett, and Teller equation (BET) surface area due to the increasing evolution of volatiles from pistachio-nut shells, resulting in enhanced pore development in biochars. For turbostratic arrangements, the successive layer planes are disposed approximately parallel and equidistant, but rotated more or less randomly with respect to each other (**Figure 2**). The spacing between the planes of turbostratic regions of biochar is larger than that observed in graphite [19].

In relating biochars with soil physical properties, biochar's particle size, shape, and internal structure play important roles in controlling soil water storage because they alter pore characteristics. For instance, biochar has pores inside particles (intrapores), which may provide additional space for water storage beyond the pore space between particles (interpores) [20]. Particle size may influence both intrapores and interpores through different processes because the size and connectivity of these particles likely differ. In addition, when applied in the field, biochar particles may have different sizes and shapes compared to soil particles. This addition of biochar grains with different shapes and sizes will change interpore characteristics (size, shape, connectivity, and volume) of soil and thus will affect water storage and mobility. For instance, fine biochar particles can fill pores between coarse soil particles, decreasing pore size and changing interpore shape.

An important physical property of biochar is its stability in the environment. However, degradation of at least some components (such as volatile matter or labile OM) of biochar may occur [21, 22]. On the other hand, subsoils are characteristically different due to variations in microbial activity and oxygen content, which affect biochar oxidation and aging.

#### **Figure 2.**

*Ideal biochar structure development with highest treatment temperature (HTT): (a) increased proportion of aromatic C, highly disordered in amorphous mass; (b) growing sheets of conjugated aromatic carbon, turbostratically arranged; and (c) structure becomes graphitic with order in the third dimension (source: [14]).*

**25**

*Biochar and Soil Physical Health*

*DOI: http://dx.doi.org/10.5772/intechopen.83706*

**3. Soil physical health and biochars**

Soil health synonymous to soil quality is usually considered to have three main aspects: physical, chemical, and biological. It is considered to be important for the assessment of the extent of land degradation or amelioration, and for identifying management practices for sustainable land use. However, the knowledge of the physical properties of soil is essential for improving soil health to achieve optimal productivity for each soil type in a given climatic condition. According to Dexter [23], soil physical health manifested in various ways. For instance, soils poor physical health are those that exhibit one or more of the following symptoms: poor water infiltration, run-off of water from the surface, hard-setting, poor aeration, poor rootability, and poor workability. On the other hand, good soil physical health occurs when soils exhibit the opposite or the absence of the conditions listed above. However, there has been no single measure of soil physical health [24] but an integration of a range of some physical properties to obtain an overall assessment.

**3.2 Soil physical health indicators as affected by biochar amendment**

amended soil in relation to some physical properties are discussed here.

g<sup>−</sup><sup>1</sup>

for kaolinite to about 750 m2

As mentioned earlier in this chapter, the effects of biochar on soil physical health indicators depend on several factors, such as biomass or feedstock type, pyrolytic condition, application rate, and environmental condition. The effects of biochar-

Surface area is an important soil physical health indicator that influences essential functions of soil fertility, including water, nutrient retention, aeration, and microbial activity [14]. For instance, the limited capacity of sandy soil to store water and plant nutrients is partly related to the relatively small surface area of its soil particles [25]. Coarse sands have a very low specific surface area of about 0.01 m2

g<sup>−</sup><sup>1</sup>

as the biochar concentration increased from 0 to 20 g kg<sup>−</sup><sup>1</sup>

Many studies have observed decreases in bulk density and increases in porosity as a result of biochar application [2, 6, 7, 26, 28]. Roughly, 2% (by weight) of biochar in

[25]. Therefore, soils containing a large fraction of clay may have high total waterholding capacities but inadequate aeration. Meanwhile, Troeh and Thompson [25] reported that high organic matter contents have the potentials to overcome the problem of too much water held in a clay soil, while increasing the water contents in a sandy soil. However, studies have shown that biochar will similarly change the physical nature of soil, having much of the same benefit of other organic amendments in this regard [2, 26]. Biochar-specific surfaces, being generally higher than sand and comparable to or higher than clay, will therefore cause a net increase in the total soil-specific surface when added as an amendment [14]. The high surface area of biochar provides space for formation of bonds and complexes with cations and anions with metals and elements of soil on its surface, which may improve the water and nutrient retention capacity of soil. A long-term soil column incubation study by Laird et al. [27] indicated increases in specific surface area of an amended clayey soil

and clays' large specific surface area ranging

for Na-exchanged montmorillonite

 g<sup>−</sup><sup>1</sup> ,

.

**3.1 What is soil physical health?**

*3.2.1 Soil surface area*

from 5 m2

compared to fine sands of 0.1 m2

g<sup>−</sup><sup>1</sup>

from 130 to 153 m2

g<sup>−</sup><sup>1</sup>

*3.2.2 Bulk density and pore-size distribution*

#### **3. Soil physical health and biochars**

#### **3.1 What is soil physical health?**

*Biochar - An Imperative Amendment for Soil and the Environment*

the biomass and biochar) [14].

affect biochar oxidation and aging.

or pyrolysis system by which they are made (including the pre- and posthandling of

The fundamental molecular structure of biochar creates both its surface area and porosity. However, pyrolysis processing of biomass enlarges the crystallites and makes them more ordered. This effect increases with highest treatment temperature. Lua et al. [15] demonstrated that increasing the pyrolysis temperature from 250 to 500°C increases the Brunauer, Emmett, and Teller equation (BET) surface area due to the increasing evolution of volatiles from pistachio-nut shells, resulting in enhanced pore development in biochars. For turbostratic arrangements, the successive layer planes are disposed approximately parallel and equidistant, but rotated more or less randomly with respect to each other (**Figure 2**). The spacing between the planes of

turbostratic regions of biochar is larger than that observed in graphite [19].

In relating biochars with soil physical properties, biochar's particle size, shape, and internal structure play important roles in controlling soil water storage because they alter pore characteristics. For instance, biochar has pores inside particles (intrapores), which may provide additional space for water storage beyond the pore space between particles (interpores) [20]. Particle size may influence both intrapores and interpores through different processes because the size and connectivity of these particles likely differ. In addition, when applied in the field, biochar particles may have different sizes and shapes compared to soil particles. This addition of biochar grains with different shapes and sizes will change interpore characteristics (size, shape, connectivity, and volume) of soil and thus will affect water storage and mobility. For instance, fine biochar particles can fill pores between coarse soil particles, decreasing pore size and changing interpore shape.

An important physical property of biochar is its stability in the environment. However, degradation of at least some components (such as volatile matter or labile OM) of biochar may occur [21, 22]. On the other hand, subsoils are characteristically different due to variations in microbial activity and oxygen content, which

*Ideal biochar structure development with highest treatment temperature (HTT): (a) increased proportion of aromatic C, highly disordered in amorphous mass; (b) growing sheets of conjugated aromatic carbon, turbostratically arranged; and (c) structure becomes graphitic with order in the third dimension (source: [14]).*

**24**

**Figure 2.**

Soil health synonymous to soil quality is usually considered to have three main aspects: physical, chemical, and biological. It is considered to be important for the assessment of the extent of land degradation or amelioration, and for identifying management practices for sustainable land use. However, the knowledge of the physical properties of soil is essential for improving soil health to achieve optimal productivity for each soil type in a given climatic condition. According to Dexter [23], soil physical health manifested in various ways. For instance, soils poor physical health are those that exhibit one or more of the following symptoms: poor water infiltration, run-off of water from the surface, hard-setting, poor aeration, poor rootability, and poor workability. On the other hand, good soil physical health occurs when soils exhibit the opposite or the absence of the conditions listed above. However, there has been no single measure of soil physical health [24] but an integration of a range of some physical properties to obtain an overall assessment.

#### **3.2 Soil physical health indicators as affected by biochar amendment**

As mentioned earlier in this chapter, the effects of biochar on soil physical health indicators depend on several factors, such as biomass or feedstock type, pyrolytic condition, application rate, and environmental condition. The effects of biocharamended soil in relation to some physical properties are discussed here.

#### *3.2.1 Soil surface area*

Surface area is an important soil physical health indicator that influences essential functions of soil fertility, including water, nutrient retention, aeration, and microbial activity [14]. For instance, the limited capacity of sandy soil to store water and plant nutrients is partly related to the relatively small surface area of its soil particles [25]. Coarse sands have a very low specific surface area of about 0.01 m2 g<sup>−</sup><sup>1</sup> , compared to fine sands of 0.1 m2 g<sup>−</sup><sup>1</sup> and clays' large specific surface area ranging from 5 m2 g<sup>−</sup><sup>1</sup> for kaolinite to about 750 m2 g<sup>−</sup><sup>1</sup> for Na-exchanged montmorillonite [25]. Therefore, soils containing a large fraction of clay may have high total waterholding capacities but inadequate aeration. Meanwhile, Troeh and Thompson [25] reported that high organic matter contents have the potentials to overcome the problem of too much water held in a clay soil, while increasing the water contents in a sandy soil. However, studies have shown that biochar will similarly change the physical nature of soil, having much of the same benefit of other organic amendments in this regard [2, 26]. Biochar-specific surfaces, being generally higher than sand and comparable to or higher than clay, will therefore cause a net increase in the total soil-specific surface when added as an amendment [14]. The high surface area of biochar provides space for formation of bonds and complexes with cations and anions with metals and elements of soil on its surface, which may improve the water and nutrient retention capacity of soil. A long-term soil column incubation study by Laird et al. [27] indicated increases in specific surface area of an amended clayey soil from 130 to 153 m2 g<sup>−</sup><sup>1</sup> as the biochar concentration increased from 0 to 20 g kg<sup>−</sup><sup>1</sup> .

#### *3.2.2 Bulk density and pore-size distribution*

Many studies have observed decreases in bulk density and increases in porosity as a result of biochar application [2, 6, 7, 26, 28]. Roughly, 2% (by weight) of biochar in

soil is an enough addition to show a significant decrease in bulk density in amended soils [6, 7]. The rate of biochar application as well as the density and porosity of the original soil are critical in predicting the effects of biochar addition to any soil. Using peanut hulls, Githinji [28] recorded reductions in bulk density with increased rate of biochar amendment, and he [28] recorded the highest bulk density of 1.33 g cm<sup>−</sup><sup>3</sup> for the soil without biochar amendment, decreasing to 1.09 g cm<sup>−</sup><sup>3</sup> for 25% rate, 0.89 g cm<sup>−</sup><sup>3</sup> for 50% rate, 0.61 g cm<sup>−</sup><sup>3</sup> for 75% rate, and 0.36 g cm<sup>−</sup><sup>3</sup> for 100% rate of biochar application. Since bulk density is a measure of the relative mass of a solid relative to the bulk volume the solid occupies, including the void spaces, it follows that the greater is the portion occupied by the pores, the lower is the bulk density of a solid. The upper limit of the bulk density would be a situation where there are no pores, and this limit will approach that of particle density of a solid.

The relationship between total surface area and pore-size distribution is logical. It is logical that this physical feature of biochars will also be of importance to their behavior in soil processes. As shown in **Figure 2**, the increase in HTT results in more structured regular spacing between the planes. Interplanar distances also decrease with the increased ordering and organization of molecules, all of which result in larger surface areas per volume. Githinji [28] reported that for the nonamended soil, porosity was 0.50 cm3 cm<sup>−</sup><sup>3</sup> , increasing to 0.55, 0.61, 0.69, and 0.78 cm3 cm<sup>−</sup><sup>3</sup> , respectively, for 25, 50, 75, and 100% rates of biochar application. In another trial comparing poultry litter biochar-amended soil and uncharred poultry manure, Are et al. [2] recorded a significance increase in storage pores (0.5–50 μm equivalent cylindrical radius) of a biochar-amended soil than uncharred poultry manure. However, this was not the case of transmission pores, where the soil amended with poultry biochar had lower transmission pores than uncharred poultry materials [2]. Mesoporosity may also increase significantly at the expense of macropores in wastederived biochar-amended soil compared to control, with the higher rate of biochar application having a greater effect [29].

#### *3.2.3 Soil water retention*

The quantification of the amount of water held at field capacity (*θfc*) and at permanent wilting point (*θpwp*), and the amount of plant available water (*θpaw*) of soil with biochar amendment is an efficient way to quantify how biochar affects soil water conditions and plant growth. Previous studies have shown that biochar increased water retention of soil [7, 30]. Gaskin et al. [31] reported a doubling in the mean volumetric water content of a loamy sandy soil at 2 kPa following the application of peanut hull biochar at a rate of 88 t/ha. Whereas Are et al. [2] also reported as high as 33% change in moisture content with application of poultry litter biochar to a sandy loam soil. However, the mechanisms controlling these observations should be understood. Sandy soils, which have larger pore space, are particularly appealing target for biochar amendment because studies on sand and sandy loam often show an increase in plant available water after biochar amendment [32, 33]. However, few studies focused on the mechanism of how biochar increase the available water. Without understanding the mechanisms that control biochar-driven changes of water retention of soil, it is difficult to predict when and by how much biochar will improve soil water retention.

Biochar's particle size, shape, and internal structure may play important roles in controlling soil water storage because they alter pore characteristics. For instance, biochar has pores inside particles (intrapores), which may provide additional space for water storage beyond the pore space between particles (interpores) [20]. Particle size may influence both intrapores and interpores through different processes because the size and connectivity of these particles likely differ. Intraporosity increases plant available water, suggesting that biochar with high intraporosity

**27**

*Biochar and Soil Physical Health*

*3.2.4 Hydraulic conductivity*

than other amendments (16.5–18.2 mm h<sup>−</sup><sup>1</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.83706*

will be most useful. Feedstock type, pyrolysis temperature, and charring residence time influence biochar's intraporosity [34]. Biochars with low intraporosity such as wastewater sludge biochar and poultry litter biochar are less favorable for soil water storage at low water potentials (<−16.5 kPa) because their internal porosity is very low [35]. In addition, the efficiency of biochar for improving soil water retention will be reduced if biochars are hydrophobic, but hydrophobicity can likely be managed by pretreatment [21]. Hydrophobic biochar has positive water entry pressure, meaning that an applied force is required for water to enter intrapores. Biochar hydrophobicity can prevent water from penetrating into biochar intrapores, prohibiting an improvement of soil water retention [10]. This indicates that biochars with low hydrophobicity will enhance soil water retention than those with high hydrophobic. Jeffery et al. [10] reported that grass species biochar did not improve soil water retention; this is probably due to its high hydrophobicity, although it is notable that grass biochar has lower hydrophobicity compared to leaf or wood biochars [9]. Biochar's hydrophobicity varies with production temperature and feedstock [36], but it is usually eliminated by brief environmental exposure. Pretreating biochar either by initially wetting it, or by composting is likely to

significantly reduce problems associated with hydrophobicity [35].

Hydraulic conductivity (*K*) measures the ease with which water can move through a soil, subject to a hydraulic gradient and is essential in infiltration-related applications such as irrigation and drainage management [37]. Saturated hydraulic conductivity (*Ksat*) is the conductivity measured, while the soil is saturated. In a trial in Ibadan, Nigeria, Are et al. [2] recorded a significant reduction in *Ksat* (9.2 mm h<sup>−</sup><sup>1</sup>

reduction in the *ksat* of poultry's biochar treatment soils was linked to the ash deposited by the biochar, which perhaps reduced the larger soil pores and thus led to the reduction in pore space and volumes. Several studies [2, 28, 38–40] have linked the reduction in soil hydraulic conductivity, especially sandy soil, to a reduction in porosity imposed by the fine-grained particles of biochar. Devaraux et al. [38] was of the opinion that the decrease was due to biochar's large surface area and the high number of pores, which had to be filled up before water drained under the force of gravity, meaning that more biochar in the soil might lead to the retention of more water in the storage pores. Barnes et al. [39], on the other hand, related shifts in *Ksat* to the physical mechanisms of the biochar, such as swelling and grain segregation, leading to the clogging of pores, decrease in pore radii, and possibly a variation in the bulk density and sample heterogeneity in the course of their experiment.

Contrasting results have been reported on the *Ksat* of a clay loam soil in Laos, following the application of biochar [40]. Asai et al. [40] reported a significant increase

produced from wood. In a study by Barnes et al. [39], *Ksat* significantly increased in clay soil, decreased in sandy soil, and had no significant effect for sandy loam rich in organic matter following incorporation of biochar. The mixed results demonstrate that the interactions between applied biochar and soil amended with biochar, and the resulting effects on hydraulic conductivity are dependent on soil texture.

Few data are available on aggregate stability and penetration resistance (PR) of biochar-amended soil. However, available information that exists is conflicting.

in *Ksat* on a clay loam soil with biochar amendment, whereas Major et al. [41] reported no significant effect in a clay soil following the addition of 20 t ha<sup>−</sup><sup>1</sup>

*3.2.5 Soil aggregate stability and penetration resistance*

) in their poultry biochar trial. The

)

biochar

#### *Biochar and Soil Physical Health DOI: http://dx.doi.org/10.5772/intechopen.83706*

*Biochar - An Imperative Amendment for Soil and the Environment*

for 50% rate, 0.61 g cm<sup>−</sup><sup>3</sup>

0.89 g cm<sup>−</sup><sup>3</sup>

soil, porosity was 0.50 cm3

*3.2.3 Soil water retention*

application having a greater effect [29].

for the soil without biochar amendment, decreasing to 1.09 g cm<sup>−</sup><sup>3</sup>

pores, and this limit will approach that of particle density of a solid.

cm<sup>−</sup><sup>3</sup>

soil is an enough addition to show a significant decrease in bulk density in amended soils [6, 7]. The rate of biochar application as well as the density and porosity of the original soil are critical in predicting the effects of biochar addition to any soil. Using peanut hulls, Githinji [28] recorded reductions in bulk density with increased rate of biochar amendment, and he [28] recorded the highest bulk density of 1.33 g cm<sup>−</sup><sup>3</sup>

of biochar application. Since bulk density is a measure of the relative mass of a solid relative to the bulk volume the solid occupies, including the void spaces, it follows that the greater is the portion occupied by the pores, the lower is the bulk density of a solid. The upper limit of the bulk density would be a situation where there are no

The relationship between total surface area and pore-size distribution is logical. It is logical that this physical feature of biochars will also be of importance to their behavior in soil processes. As shown in **Figure 2**, the increase in HTT results in more structured regular spacing between the planes. Interplanar distances also decrease with the increased ordering and organization of molecules, all of which result in larger surface areas per volume. Githinji [28] reported that for the nonamended

respectively, for 25, 50, 75, and 100% rates of biochar application. In another trial comparing poultry litter biochar-amended soil and uncharred poultry manure, Are et al. [2] recorded a significance increase in storage pores (0.5–50 μm equivalent cylindrical radius) of a biochar-amended soil than uncharred poultry manure. However, this was not the case of transmission pores, where the soil amended with poultry biochar had lower transmission pores than uncharred poultry materials [2]. Mesoporosity may also increase significantly at the expense of macropores in wastederived biochar-amended soil compared to control, with the higher rate of biochar

The quantification of the amount of water held at field capacity (*θfc*) and at permanent wilting point (*θpwp*), and the amount of plant available water (*θpaw*) of soil with biochar amendment is an efficient way to quantify how biochar affects soil water conditions and plant growth. Previous studies have shown that biochar increased water retention of soil [7, 30]. Gaskin et al. [31] reported a doubling in the mean volumetric water content of a loamy sandy soil at 2 kPa following the application of peanut hull biochar at a rate of 88 t/ha. Whereas Are et al. [2] also reported as high as 33% change in moisture content with application of poultry litter biochar to a sandy loam soil. However, the mechanisms controlling these observations should be understood. Sandy soils, which have larger pore space, are particularly appealing target for biochar amendment because studies on sand and sandy loam often show an increase in plant available water after biochar amendment [32, 33]. However, few studies focused on the mechanism of how biochar increase the available water. Without understanding the mechanisms that control biochar-driven changes of water retention of soil, it is difficult to predict when and by how much biochar will improve soil water retention. Biochar's particle size, shape, and internal structure may play important roles in controlling soil water storage because they alter pore characteristics. For instance, biochar has pores inside particles (intrapores), which may provide additional space for water storage beyond the pore space between particles (interpores) [20]. Particle size may influence both intrapores and interpores through different processes because the size and connectivity of these particles likely differ. Intraporosity increases plant available water, suggesting that biochar with high intraporosity

for 75% rate, and 0.36 g cm<sup>−</sup><sup>3</sup>

, increasing to 0.55, 0.61, 0.69, and 0.78 cm3

for 25% rate,

for 100% rate

 cm<sup>−</sup><sup>3</sup> ,

**26**

will be most useful. Feedstock type, pyrolysis temperature, and charring residence time influence biochar's intraporosity [34]. Biochars with low intraporosity such as wastewater sludge biochar and poultry litter biochar are less favorable for soil water storage at low water potentials (<−16.5 kPa) because their internal porosity is very low [35]. In addition, the efficiency of biochar for improving soil water retention will be reduced if biochars are hydrophobic, but hydrophobicity can likely be managed by pretreatment [21]. Hydrophobic biochar has positive water entry pressure, meaning that an applied force is required for water to enter intrapores. Biochar hydrophobicity can prevent water from penetrating into biochar intrapores, prohibiting an improvement of soil water retention [10]. This indicates that biochars with low hydrophobicity will enhance soil water retention than those with high hydrophobic. Jeffery et al. [10] reported that grass species biochar did not improve soil water retention; this is probably due to its high hydrophobicity, although it is notable that grass biochar has lower hydrophobicity compared to leaf or wood biochars [9]. Biochar's hydrophobicity varies with production temperature and feedstock [36], but it is usually eliminated by brief environmental exposure. Pretreating biochar either by initially wetting it, or by composting is likely to significantly reduce problems associated with hydrophobicity [35].

#### *3.2.4 Hydraulic conductivity*

Hydraulic conductivity (*K*) measures the ease with which water can move through a soil, subject to a hydraulic gradient and is essential in infiltration-related applications such as irrigation and drainage management [37]. Saturated hydraulic conductivity (*Ksat*) is the conductivity measured, while the soil is saturated. In a trial in Ibadan, Nigeria, Are et al. [2] recorded a significant reduction in *Ksat* (9.2 mm h<sup>−</sup><sup>1</sup> ) than other amendments (16.5–18.2 mm h<sup>−</sup><sup>1</sup> ) in their poultry biochar trial. The reduction in the *ksat* of poultry's biochar treatment soils was linked to the ash deposited by the biochar, which perhaps reduced the larger soil pores and thus led to the reduction in pore space and volumes. Several studies [2, 28, 38–40] have linked the reduction in soil hydraulic conductivity, especially sandy soil, to a reduction in porosity imposed by the fine-grained particles of biochar. Devaraux et al. [38] was of the opinion that the decrease was due to biochar's large surface area and the high number of pores, which had to be filled up before water drained under the force of gravity, meaning that more biochar in the soil might lead to the retention of more water in the storage pores. Barnes et al. [39], on the other hand, related shifts in *Ksat* to the physical mechanisms of the biochar, such as swelling and grain segregation, leading to the clogging of pores, decrease in pore radii, and possibly a variation in the bulk density and sample heterogeneity in the course of their experiment.

Contrasting results have been reported on the *Ksat* of a clay loam soil in Laos, following the application of biochar [40]. Asai et al. [40] reported a significant increase in *Ksat* on a clay loam soil with biochar amendment, whereas Major et al. [41] reported no significant effect in a clay soil following the addition of 20 t ha<sup>−</sup><sup>1</sup> biochar produced from wood. In a study by Barnes et al. [39], *Ksat* significantly increased in clay soil, decreased in sandy soil, and had no significant effect for sandy loam rich in organic matter following incorporation of biochar. The mixed results demonstrate that the interactions between applied biochar and soil amended with biochar, and the resulting effects on hydraulic conductivity are dependent on soil texture.

#### *3.2.5 Soil aggregate stability and penetration resistance*

Few data are available on aggregate stability and penetration resistance (PR) of biochar-amended soil. However, available information that exists is conflicting. Examples of the few studies, which investigated soil aggregation with biochar amendment, are shown in **Table 1**. In a study by George et al. [42], the low-temperature (220°C) hydrochar made from spent brewer's grains, a residue from beer brewing, responded positively on aggregation of Albic Luvisol when (i) incubated for 5 months at 20°C in dark and (ii) used in a pot study with same hydrochar/soil combination (**Table 1**). These incubation and greenhouse studies involving plant indicate that hydrochar significantly increased water stable aggregates (WSA) compared to control, but the extent of WSA differed because the greenhouse study had 2–5 times higher rate of WSA formation compared to laboratory incubation. These data suggest that plant roots and mycorrhizal fungi, which were absent in the incubation study, had an important role in soil aggregation. In a field experiment, Are et al. [2] found that the poultry biochar amendment increased the WSA of a sandy loam soil from 41.6 to 59.1% of a four-season trial. In contrast, with and without mixing Bt and E horizons with pecan shell (*Carya illinoinensis*), biochar amendment decreased aggregation (**Table 1**) compared to control [43]. Mixing of biochar from pecan with switchgrass increased aggregation; however, the effect was significantly lower when soil was treated only with biochar and without mixing with switchgrass [44]. This trend indicates that a positive effect on soil aggregate stability requires presence of a substrate (i.e., switchgrass) along with biochar as an amendment. However, the application of biochar at the rate of 1% to an ultisol had no effect on aggregate stability [45]. Clearly, there exists limited information


**29**

*Biochar and Soil Physical Health*

biochar and soil type.

aggregates and water retention.

**Acknowledgements**

**Conflict of interest**

this chapter.

**4. Conclusions**

*DOI: http://dx.doi.org/10.5772/intechopen.83706*

which ultimately increased the aggregate stability.

about how biochar affects aggregation and whether another substrate, plant roots, mycorrhizal fungi, or active-C source might be needed to increase WSA in biocharamended soils. Nevertheless, the highest concentration of black-C was observed in the finest size fraction (<0.53 μm) of soil aggregates [46] suggesting preferential embedding of black-C particles compared to other organic compounds within aggregates. However, it was suggested by Jeffery et al. [10] that the hydrophobicity of biochar [10] may have increased the resistance of aggregates to slaking in water,

The resistance of the soil to root penetration as determined by cone penetration resistance (PR) may not be alleviated by biochar addition over short time period but may be altered in the long run as aging of biochar changes its properties [47]. Along with time, soil type is also an important factor because another study reported reduction in PR with application of the same biochar on a different soil type (Norfolk loamy sand Ap) [44]. Nevertheless, the effect of biochar amendment on soil aggregation and PR requires additional research by including variations in

This review synthesizes available data on soil physical health indicators as influenced by application of biochars. The physical properties of biochar products affect many of the functional roles that they may play in improving soil physical health and environmental management. The large variation of physical characteristics observed in different biochar products means that some will be more effective than others in certain applications. It is important that the physical characterization of biochars is undertaken before they are experimentally applied to environmental systems, and variations in outcomes may be correlated with these features. The pyrolysis temperature, charring time of biochar and most importantly, the particle size of biochar play important factors in order to implement any biochar amendment project. The higher the biochar pyrolysis temperature, the finer the particle size, and the higher are the bulk density and water retention. The relationship may be inverse in relation to soil hydraulic conductivity and pore size distribution. This, however, depends on the soil type. Evidence has shown that biochar with finer particles when applied to sandy soil will reduce the macropores and hydraulic conductivity, whereas, in a clayey soil, biochar with finer particles will increase the interpores and soil hydraulic conductivity. Application rates of 0.25–2% (g g<sup>−</sup><sup>1</sup>

biochar can significantly improve soil physical health in terms of water-stable

I wish to acknowledge the support enjoyed from the Institute of Agricultural Research and Training, Ibadan, Nigeria, for providing enabling environment to carry out biochar research. My appreciation goes to Biochar Initiatives in Nigeria, and to Ms. Romina Skomersic, whose encouragement geared me up in submitting

The author declares that there is no conflict of interest.

)

*Measured after 96 days. \* With switchgrass addition.*

#### **Table 1.**

*Impact of biochar on aggregation and penetration resistance.*

#### *Biochar and Soil Physical Health DOI: http://dx.doi.org/10.5772/intechopen.83706*

about how biochar affects aggregation and whether another substrate, plant roots, mycorrhizal fungi, or active-C source might be needed to increase WSA in biocharamended soils. Nevertheless, the highest concentration of black-C was observed in the finest size fraction (<0.53 μm) of soil aggregates [46] suggesting preferential embedding of black-C particles compared to other organic compounds within aggregates. However, it was suggested by Jeffery et al. [10] that the hydrophobicity of biochar [10] may have increased the resistance of aggregates to slaking in water, which ultimately increased the aggregate stability.

The resistance of the soil to root penetration as determined by cone penetration resistance (PR) may not be alleviated by biochar addition over short time period but may be altered in the long run as aging of biochar changes its properties [47]. Along with time, soil type is also an important factor because another study reported reduction in PR with application of the same biochar on a different soil type (Norfolk loamy sand Ap) [44]. Nevertheless, the effect of biochar amendment on soil aggregation and PR requires additional research by including variations in biochar and soil type.

#### **4. Conclusions**

*Biochar - An Imperative Amendment for Soil and the Environment*

**Soil type Biochar type Study type** 

Pecan shells, 700°C

Pecan shells, 700°C

220°C

*Impact of biochar on aggregation and penetration resistance.*

Norfolk loamy sand: E

Norfolk loamy sand: E and Bt

Norfolk loamy sand: Ap

Albic Luvisol Hydrochar,

**(scale)**

**Rate of biochar application % (g g<sup>−</sup><sup>1</sup> )**

**Aggregation (%)**

2.1 12.9 1.27a 0.88b

0 27.3 0.71a 0.76b 2.1 20.9 0.88a 0.94b

0.5 9.53 12.7\* 0.96a 1.15b 1.0 10.7 12.3\* 1.03a 1.02b 2.0 9.23 11.8\* 0.82a 0.87<sup>b</sup>

5 69.0 — — — 10 65.1 — — —

5 20.8 — — — 10 33.8 — — —

0.25 59.1 — — —

Laboratory 0 14.3 1.19a 0.80b [43]

Laboratory 0 9.95 13.0\* 1.04a 1.10b [44]

Laboratory 0 49.8 — — — [42]

Greenhouse 0 10.3 — — —

Alfisol Field 0 41.6 — — — [2]

**Penetration resistance (MPa)**

**Source**

Examples of the few studies, which investigated soil aggregation with biochar amendment, are shown in **Table 1**. In a study by George et al. [42], the low-temperature (220°C) hydrochar made from spent brewer's grains, a residue from beer brewing, responded positively on aggregation of Albic Luvisol when (i) incubated for 5 months at 20°C in dark and (ii) used in a pot study with same hydrochar/soil combination (**Table 1**). These incubation and greenhouse studies involving plant indicate that hydrochar significantly increased water stable aggregates (WSA) compared to control, but the extent of WSA differed because the greenhouse study had 2–5 times higher rate of WSA formation compared to laboratory incubation. These data suggest that plant roots and mycorrhizal fungi, which were absent in the incubation study, had an important role in soil aggregation. In a field experiment, Are et al. [2] found that the poultry biochar amendment increased the WSA of a sandy loam soil from 41.6 to 59.1% of a four-season trial. In contrast, with and without mixing Bt and E horizons with pecan shell (*Carya illinoinensis*), biochar amendment decreased aggregation (**Table 1**) compared to control [43]. Mixing of biochar from pecan with switchgrass increased aggregation; however, the effect was significantly lower when soil was treated only with biochar and without mixing with switchgrass [44]. This trend indicates that a positive effect on soil aggregate stability requires presence of a substrate (i.e., switchgrass) along with biochar as an amendment. However, the application of biochar at the rate of 1% to an ultisol had no effect on aggregate stability [45]. Clearly, there exists limited information

**28**

*a*

*b*

*\**

**Table 1.**

*Measured after 44 days.*

*Measured after 96 days.*

*With switchgrass addition.*

This review synthesizes available data on soil physical health indicators as influenced by application of biochars. The physical properties of biochar products affect many of the functional roles that they may play in improving soil physical health and environmental management. The large variation of physical characteristics observed in different biochar products means that some will be more effective than others in certain applications. It is important that the physical characterization of biochars is undertaken before they are experimentally applied to environmental systems, and variations in outcomes may be correlated with these features. The pyrolysis temperature, charring time of biochar and most importantly, the particle size of biochar play important factors in order to implement any biochar amendment project. The higher the biochar pyrolysis temperature, the finer the particle size, and the higher are the bulk density and water retention. The relationship may be inverse in relation to soil hydraulic conductivity and pore size distribution. This, however, depends on the soil type. Evidence has shown that biochar with finer particles when applied to sandy soil will reduce the macropores and hydraulic conductivity, whereas, in a clayey soil, biochar with finer particles will increase the interpores and soil hydraulic conductivity. Application rates of 0.25–2% (g g<sup>−</sup><sup>1</sup> ) biochar can significantly improve soil physical health in terms of water-stable aggregates and water retention.

#### **Acknowledgements**

I wish to acknowledge the support enjoyed from the Institute of Agricultural Research and Training, Ibadan, Nigeria, for providing enabling environment to carry out biochar research. My appreciation goes to Biochar Initiatives in Nigeria, and to Ms. Romina Skomersic, whose encouragement geared me up in submitting this chapter.

#### **Conflict of interest**

The author declares that there is no conflict of interest.

*Biochar - An Imperative Amendment for Soil and the Environment*

### **Author details**

Kayode S. Are Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria

\*Address all correspondence to: kayodeare@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**31**

*Biochar and Soil Physical Health*

*DOI: http://dx.doi.org/10.5772/intechopen.83706*

China plain. Ying Yong Sheng Tai Xue

[9] Kinney TJ, Masiello CA, Dugan B, Hockaday WC, Dean MR, Zygourakis K, et al. Hydrologic properties of biochars produced at different temperatures. Biomass and Bioenergy. 2012;**41**:34-43. DOI: 10.1016/j.biombioe.2012.01.033

[10] Jeffery S, Verheijen FGA, van der Velde M, Bastos AC. A quantitative review of the effects of biochar

application to soils on crop productivity using meta-analysis. Agriculture, Ecosystems & Environment.

[11] Mukherjee A, Lal R. The biochar dilemma. Soil Research. 2014;**52**:217-230

[12] Tryon EH. Effect of charcoal on certain physical, chemical, and biological properties of forest soils. Ecological Monographs. 1948;**18**:81-115.

[13] Masiello C, Dugan B, Brewer C, Spokas K, Novak J, Liu Z. Biochar effects on soil hydrology. In: Biochar for Environmental Management Science, Technology and Implementation. 2nd ed. United Kingdom: Routledge; 2015

[14] Downie A, Crosky A, Munroe P. Physical properties of biochar. In: Lemman J, Joseph S, editors. Biochar for Environmental Management: Science and Technology. London, UK:

[15] Lua AC, Yang T, Guo J. Effects of pyrolysis conditions on the properties of activated carbons prepared from pistachio-nut shells. Journal of Analytical and Applied Pyrolysis.

[16] Boateng AA. Characterization and thermal conversion of charcoal derived from fluidized-bed fast pyrolysis oil

Earthscan; 2009. pp. 13-32

2004;**72**:279-287

2011;**144**:175-187

DOI: 10.2307/1948629

Bao. 2011;**22**(11):2930-2934

[1] McKenzie BM, Tisdall JM, Vance WH. Soil physical quality. In: Gliński J, Horabik J, Lipiec J, editors. Encyclopedia

of Agrophysics. The Netherlands: Springer Science + Business Media B.V;

[2] Are KS, Adelana AO, Fademi IO, Aina OA. Improving physical properties of degraded soil: Potential of poultry manure and biochar. Agriculture and Natural Resources. 2017;**51**:454-462

introduction. In: Lehmann J, Joseph S, editors. Biochar for Environmental Management. London: Earthscan; 2009.

[4] Lehmann J, Rondon M. Bio-char soil management on highly weathered soils in the humid tropics. In: Uphoff N, Ball AS, Palm C, Fernandes E, Pretty J, Herrren H, Sanchez P, Husson O, Sanginga N, Laing M, Thies J, editors. Biological Approaches to Sustainable Soil Systems. Boca Raton, FL: CRC

[5] Oguntade PG, Abiodun BJ, Ajayi AE, Van de Giesen N. Effetcs of charcoal production on soil physical properties in Ghana. Journal of Plant Nutrition and

[3] Lehmann J, Joseph S. An

Press; 2006. pp. 517-530

Soil Science. 2008;**171**:591-596

[6] Mukherjee A, Lal R. Biochar impacts on soil physical properties and greenhouse gas emissions. Agronomy.

[7] Major J, Lehmann J, Rondon M. Biochar application to a topical oxisol modifies water relations. In: Poster at the 2006 World Soil Congress;

[8] Chen HX, Du ZL, Guo W, Zhang QZ. Effects of biochar amendment on cropland soil bulk density, cation exchange capacity, and particulate organic matter content in the North

2013;**3**:313-339

Philadelphia, PA. 2006

2011. pp. 770-777

**References**

pp. 1-9

*Biochar and Soil Physical Health DOI: http://dx.doi.org/10.5772/intechopen.83706*

#### **References**

*Biochar - An Imperative Amendment for Soil and the Environment*

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Institute of Agricultural Research and Training, Obafemi Awolowo University,

**30**

**Author details**

Kayode S. Are

provided the original work is properly cited.

\*Address all correspondence to: kayodeare@gmail.com

Moor Plantation, Ibadan, Nigeria

[1] McKenzie BM, Tisdall JM, Vance WH. Soil physical quality. In: Gliński J, Horabik J, Lipiec J, editors. Encyclopedia of Agrophysics. The Netherlands: Springer Science + Business Media B.V; 2011. pp. 770-777

[2] Are KS, Adelana AO, Fademi IO, Aina OA. Improving physical properties of degraded soil: Potential of poultry manure and biochar. Agriculture and Natural Resources. 2017;**51**:454-462

[3] Lehmann J, Joseph S. An introduction. In: Lehmann J, Joseph S, editors. Biochar for Environmental Management. London: Earthscan; 2009. pp. 1-9

[4] Lehmann J, Rondon M. Bio-char soil management on highly weathered soils in the humid tropics. In: Uphoff N, Ball AS, Palm C, Fernandes E, Pretty J, Herrren H, Sanchez P, Husson O, Sanginga N, Laing M, Thies J, editors. Biological Approaches to Sustainable Soil Systems. Boca Raton, FL: CRC Press; 2006. pp. 517-530

[5] Oguntade PG, Abiodun BJ, Ajayi AE, Van de Giesen N. Effetcs of charcoal production on soil physical properties in Ghana. Journal of Plant Nutrition and Soil Science. 2008;**171**:591-596

[6] Mukherjee A, Lal R. Biochar impacts on soil physical properties and greenhouse gas emissions. Agronomy. 2013;**3**:313-339

[7] Major J, Lehmann J, Rondon M. Biochar application to a topical oxisol modifies water relations. In: Poster at the 2006 World Soil Congress; Philadelphia, PA. 2006

[8] Chen HX, Du ZL, Guo W, Zhang QZ. Effects of biochar amendment on cropland soil bulk density, cation exchange capacity, and particulate organic matter content in the North

China plain. Ying Yong Sheng Tai Xue Bao. 2011;**22**(11):2930-2934

[9] Kinney TJ, Masiello CA, Dugan B, Hockaday WC, Dean MR, Zygourakis K, et al. Hydrologic properties of biochars produced at different temperatures. Biomass and Bioenergy. 2012;**41**:34-43. DOI: 10.1016/j.biombioe.2012.01.033

[10] Jeffery S, Verheijen FGA, van der Velde M, Bastos AC. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agriculture, Ecosystems & Environment. 2011;**144**:175-187

[11] Mukherjee A, Lal R. The biochar dilemma. Soil Research. 2014;**52**:217-230

[12] Tryon EH. Effect of charcoal on certain physical, chemical, and biological properties of forest soils. Ecological Monographs. 1948;**18**:81-115. DOI: 10.2307/1948629

[13] Masiello C, Dugan B, Brewer C, Spokas K, Novak J, Liu Z. Biochar effects on soil hydrology. In: Biochar for Environmental Management Science, Technology and Implementation. 2nd ed. United Kingdom: Routledge; 2015

[14] Downie A, Crosky A, Munroe P. Physical properties of biochar. In: Lemman J, Joseph S, editors. Biochar for Environmental Management: Science and Technology. London, UK: Earthscan; 2009. pp. 13-32

[15] Lua AC, Yang T, Guo J. Effects of pyrolysis conditions on the properties of activated carbons prepared from pistachio-nut shells. Journal of Analytical and Applied Pyrolysis. 2004;**72**:279-287

[16] Boateng AA. Characterization and thermal conversion of charcoal derived from fluidized-bed fast pyrolysis oil

production of switch grass. Industrial Engineering and Chemical Research. 2007;**46**:8857-8862

[17] Byrne CE, Nagle DC. Carbonized wood monoliths – Characterization. Carbon. 1997;**35**:267-273

[18] Brown RA, Kercher AK, Nguyen TH, Nagle DC, Ball WP. Production and characterization of synthetic wood chars for use as surrogates for natural sorbents. Organic Geochemistry. 2006;**37**:321-333

[19] Emmerich FG, Sousa JC, Torriani IL, Luengo CA. Applications of a granular model and percolation theory to the electrical resistivity of heat treated endocarp of babassu nut. Carbon. 1987;**25**:417-424

[20] Liu Z, Dugan B, Masiello CA, Gonnermann HM. Biochar particle size, shape, and porosity act together to influence soil water properties. PLoS One. 2017;**12**(6):e0179079. DOI: 10.1371/journal.pone.0179079

[21] Zimmerman AR. Abiotic and microbial oxidation of laboratoryproduced black carbon (biochar). Environmental Science & Technology. 2010;**44**:1295-1301

[22] Hammes K, Torn MS, Lapenas AG, Schmidt MWI. Centennial black carbon turnover observed in a Russian steppe soil. Biogeosciences. 2008;**5**:1339-1350

[23] Dexter AR. Soil physical quality. Part I. Theory, effects of soil texture, density, and organic matter, and effects on root growth. Geoderma. 2004;**120**:201-214

[24] Dexter AR, Czyz EA. Soil physical quality and the effects of management practices. In: Wilson MJ, Maliszewska-Kordybach B, editors. Soil Quality, Sustainable Agriculture and Environmental Security in Central and Eastern Europe. NATO Science

Series 2, Environmental Security. Vol. 69. Dordrecht: Kluwer Academic Publishers; 2000. pp. 153-165

[25] Troeh FR, Thompson LM. Soils and Soil Fertility. Iowa, US: Blackwell Publishing; 2005

[26] Chan KY, Van Zwieten L, Meszaros I, Downie A, Joseph S. Agronomic values of green-waste biochar as a soil amendment. Australian Journal of Soil Research. 2007;**45**:629-634

[27] Laird DA, Fleming P, Davis DD, Horton R, Wang BQ, Karlen DL. Impact of biochar amendments on the quality of a typical midwestern agricultural soil. Geoderma. 2010;**158**:443-449

[28] Githinji L. Effect of biochar application rate on soil physical and hydraulic properties of a sandy loam. Archives of Agronomy and Soil Science. 2014;**60**:457-470

[29] Jones BEH, Haynes RJ, Phillips IR. Effect of amendment of bauxite processing sand with organic materials on its chemical, physical and microbial properties. Journal of Environmental Management. 2010;**91**:2281-2288

[30] Scott HL, Ponsonby D, Atkinson CJ. Biochar: An improver of nutrient and soil water availability? What is the evidence? CAB Reviews. 2014;**9**(019):1-19

[31] Gaskin JW, Speir A, Morris LM, Ogden L, Harris K, Lee D, Das KC. Potential for pyrolysis char to affect soil moisture and nutrient status of loamy sand soil. Proceedings of the Georgia Water Resources Conference; University of Georgia, USA. 2007

[32] Omondi MO, Xia X, Nahayo A, Liu X, Korai PK, Pan G. Quantification of biochar effects on soil hydrological properties using meta-analysis of literature data. Geoderma. 2016;**274**:28-34

**33**

*Biochar and Soil Physical Health*

2016;**161**:1-9

*DOI: http://dx.doi.org/10.5772/intechopen.83706*

[40] Asai H, Benjamin SK, Haefele SM, Khamdok S, Koki H, Yoshiyuki K, et al. Biochar amendment techniques for upland rice production in Northern Laos: 1. Soil physical properties, leaf SPAD and grain yield. Field Crops

[41] Major J, Rondon M, Molina D, Riha SJ, Lehmann J. Nutrient leaching in a Colombian savanna oxisol amended with biochar. Journal of Environmental

[42] George C, Wagner M, Kucke M, Rillig MC. Divergent consequences of hydrochar in the plant-soil system: Arbuscular mycorrhiza, nodulation, plant growth and soil aggregation effects. Applied Soil Ecology.

[43] Busscher WJ, Novak JM, Ahmedna M. Physical effects of organic matter amendment of a southeastern us coastal loamy sand. Soil Science.

[44] Busscher WJ, Novak JM, Evans DE, Watts DW, Niandou MAS, Ahmedna M. Influence of pecan biochar on physical properties of a Norfolk loamy sand. Soil Science. 2010;**175**:10-14

[45] Peng X, Ye LL, Wang CH, Zhou H, Sun B. Temperature- and durationdependent rice straw-derived biochar: Characteristics and its effects on soil properties of an ultisol in southern China. Soil and Tillage Research.

[46] Brodowski S, John B, Flessa H, Amelung W. Aggregate-occluded black carbon in soil. European Journal of Soil

[47] Mukherjee A. Physical and chemical properties of a range of laboratoryproduced fresh and aged biochars [Ph.D. thesis]. Gainesville, FL, USA:

Science. 2006;**57**:539-546

University of Florida; 2011

Research. 2009;**111**:81-84

Qualilty. 2012;**41**:1076-1086

2012;**59**:68-72

2011;**176**:661-667

2011;**112**:159-166

[33] Hansen V, Hauggaard-Nielsen H, Petersen CT, Mikkelsen TN, Müller-Stöver D. Effects of gasification biochar on plant-available water capacity and plant growth in two contrasting soil types. Soil and Tillage Research.

[34] Brewer CE, Chuang VJ, Masiello CA, Gonnermann H, Gao X, Dugan B, et al. New approaches to measuring biochar density and porosity. Biomass and Bioenergy. 2014;**66**:176-185

[35] Waqas M, Li G, Khan S, Shamshad I, Reid BJ, Qamar Z, et al. Application

of sewage sludge and sewage sludge biochar to reduce polycyclic aromatic hydrocarbons (PAH) and potentially toxic elements (PTE) accumulation in tomato. Environmental

Science and Pollution Research. 2015;**22**(16):12114-12123

2013;**47**:821-828

1999;**63**:788-792

[36] Wang D, Zhang W, Hao X, Zhou D. Transport of biochar particles in saturated granular media: Effects of pyrolysis temperature and particle size. Environmental Science and Technology.

[37] Wu L, Pan L, Mitchell J, Sanden B.

[38] Deveraux RC, Sturrock CJ, Mooney SJ. The effects of biochar on soil physical properties and winter wheat growth. Earth and Environmental Science Transactions of the Royal Society of

[39] Barnes RT, Gallagher ME, Masiello CA, Liu Z, Dugan B. Biochar-induced changes in soil hydraulic conductivity

constrained by laboratory experiments. PLoS One. 2014;**9**:e108340. DOI: 10.1371/journal.pone.0108340

Measuring saturated hydraulic conductivity using a generalized solution for single-ring infiltrometers. Soil Science Society of America Journal.

Edinburgh. 2012;**103**:13-18

and dissolved nutrient fluxes

#### *Biochar and Soil Physical Health DOI: http://dx.doi.org/10.5772/intechopen.83706*

*Biochar - An Imperative Amendment for Soil and the Environment*

Series 2, Environmental Security. Vol. 69. Dordrecht: Kluwer Academic

[25] Troeh FR, Thompson LM. Soils and Soil Fertility. Iowa, US: Blackwell

[26] Chan KY, Van Zwieten L, Meszaros I, Downie A, Joseph S. Agronomic values of green-waste biochar as a soil amendment. Australian Journal of Soil

[27] Laird DA, Fleming P, Davis DD, Horton R, Wang BQ, Karlen DL. Impact of biochar amendments on the quality of a typical midwestern agricultural soil.

Publishers; 2000. pp. 153-165

Research. 2007;**45**:629-634

Geoderma. 2010;**158**:443-449

2014;**60**:457-470

[28] Githinji L. Effect of biochar application rate on soil physical and hydraulic properties of a sandy loam. Archives of Agronomy and Soil Science.

[29] Jones BEH, Haynes RJ, Phillips IR. Effect of amendment of bauxite processing sand with organic materials on its chemical, physical and microbial properties. Journal of Environmental Management. 2010;**91**:2281-2288

[30] Scott HL, Ponsonby D, Atkinson CJ. Biochar: An improver of nutrient and soil water availability? What is the evidence?

CAB Reviews. 2014;**9**(019):1-19

of Georgia, USA. 2007

2016;**274**:28-34

[31] Gaskin JW, Speir A, Morris LM, Ogden L, Harris K, Lee D, Das KC. Potential for pyrolysis char to affect soil moisture and nutrient status of loamy sand soil. Proceedings of the Georgia Water Resources Conference; University

[32] Omondi MO, Xia X, Nahayo A, Liu X, Korai PK, Pan G. Quantification of biochar effects on soil hydrological properties using meta-analysis of literature data. Geoderma.

Publishing; 2005

production of switch grass. Industrial Engineering and Chemical Research.

[17] Byrne CE, Nagle DC. Carbonized wood monoliths – Characterization.

[18] Brown RA, Kercher AK, Nguyen TH, Nagle DC, Ball WP. Production and characterization of synthetic wood chars for use as surrogates for natural sorbents. Organic Geochemistry.

[19] Emmerich FG, Sousa JC, Torriani IL, Luengo CA. Applications of a granular model and percolation theory to the electrical resistivity of heat treated endocarp of babassu nut.

2007;**46**:8857-8862

2006;**37**:321-333

Carbon. 1997;**35**:267-273

Carbon. 1987;**25**:417-424

[20] Liu Z, Dugan B, Masiello CA, Gonnermann HM. Biochar particle size, shape, and porosity act together to influence soil water properties. PLoS One. 2017;**12**(6):e0179079. DOI:

10.1371/journal.pone.0179079

2010;**44**:1295-1301

2004;**120**:201-214

[21] Zimmerman AR. Abiotic and microbial oxidation of laboratoryproduced black carbon (biochar). Environmental Science & Technology.

[22] Hammes K, Torn MS, Lapenas AG, Schmidt MWI. Centennial black carbon turnover observed in a Russian steppe soil. Biogeosciences. 2008;**5**:1339-1350

[23] Dexter AR. Soil physical quality. Part I. Theory, effects of soil texture, density, and organic matter, and effects on root growth. Geoderma.

[24] Dexter AR, Czyz EA. Soil physical quality and the effects of management practices. In: Wilson MJ, Maliszewska-Kordybach B, editors. Soil Quality, Sustainable Agriculture and Environmental Security in Central and Eastern Europe. NATO Science

**32**

[33] Hansen V, Hauggaard-Nielsen H, Petersen CT, Mikkelsen TN, Müller-Stöver D. Effects of gasification biochar on plant-available water capacity and plant growth in two contrasting soil types. Soil and Tillage Research. 2016;**161**:1-9

[34] Brewer CE, Chuang VJ, Masiello CA, Gonnermann H, Gao X, Dugan B, et al. New approaches to measuring biochar density and porosity. Biomass and Bioenergy. 2014;**66**:176-185

[35] Waqas M, Li G, Khan S, Shamshad I, Reid BJ, Qamar Z, et al. Application of sewage sludge and sewage sludge biochar to reduce polycyclic aromatic hydrocarbons (PAH) and potentially toxic elements (PTE) accumulation in tomato. Environmental Science and Pollution Research. 2015;**22**(16):12114-12123

[36] Wang D, Zhang W, Hao X, Zhou D. Transport of biochar particles in saturated granular media: Effects of pyrolysis temperature and particle size. Environmental Science and Technology. 2013;**47**:821-828

[37] Wu L, Pan L, Mitchell J, Sanden B. Measuring saturated hydraulic conductivity using a generalized solution for single-ring infiltrometers. Soil Science Society of America Journal. 1999;**63**:788-792

[38] Deveraux RC, Sturrock CJ, Mooney SJ. The effects of biochar on soil physical properties and winter wheat growth. Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 2012;**103**:13-18

[39] Barnes RT, Gallagher ME, Masiello CA, Liu Z, Dugan B. Biochar-induced changes in soil hydraulic conductivity and dissolved nutrient fluxes constrained by laboratory experiments. PLoS One. 2014;**9**:e108340. DOI: 10.1371/journal.pone.0108340

[40] Asai H, Benjamin SK, Haefele SM, Khamdok S, Koki H, Yoshiyuki K, et al. Biochar amendment techniques for upland rice production in Northern Laos: 1. Soil physical properties, leaf SPAD and grain yield. Field Crops Research. 2009;**111**:81-84

[41] Major J, Rondon M, Molina D, Riha SJ, Lehmann J. Nutrient leaching in a Colombian savanna oxisol amended with biochar. Journal of Environmental Qualilty. 2012;**41**:1076-1086

[42] George C, Wagner M, Kucke M, Rillig MC. Divergent consequences of hydrochar in the plant-soil system: Arbuscular mycorrhiza, nodulation, plant growth and soil aggregation effects. Applied Soil Ecology. 2012;**59**:68-72

[43] Busscher WJ, Novak JM, Ahmedna M. Physical effects of organic matter amendment of a southeastern us coastal loamy sand. Soil Science. 2011;**176**:661-667

[44] Busscher WJ, Novak JM, Evans DE, Watts DW, Niandou MAS, Ahmedna M. Influence of pecan biochar on physical properties of a Norfolk loamy sand. Soil Science. 2010;**175**:10-14

[45] Peng X, Ye LL, Wang CH, Zhou H, Sun B. Temperature- and durationdependent rice straw-derived biochar: Characteristics and its effects on soil properties of an ultisol in southern China. Soil and Tillage Research. 2011;**112**:159-166

[46] Brodowski S, John B, Flessa H, Amelung W. Aggregate-occluded black carbon in soil. European Journal of Soil Science. 2006;**57**:539-546

[47] Mukherjee A. Physical and chemical properties of a range of laboratoryproduced fresh and aged biochars [Ph.D. thesis]. Gainesville, FL, USA: University of Florida; 2011

**35**

**Chapter 3**

**Abstract**

**1. Introduction**

sequestration to reduce GHG emissions [1, 2].

Increasing the Amount of

Enhancement Using Biochar

*Saowanee Wijitkosum and Thavivongse Sriburi*

Biomass in Field Crops for Carbon

The agricultural sector, especially in developing countries, is vulnerable to the effects of climate change partially caused by greenhouse gas (GHG) emissions from agricultural areas. Field crops are capable of bio-sequestration in its aboveground and belowground biomass. Incorporating biochar as a soil amendment increases its potential to become an important bio-sequestration which makes the agricultural sector a key contributor to climate change mitigation. This chapter discussed and presented data obtained from research on biochar using to increase plant biomass for carbon sequestration purposes. The biochar was produced from cassava stems by pyrolysis using a patented retort that was especially designed for agriculturalists to produce a low-cost biochar for their own use. The ability to increase biomass of field crops for carbon sequestration is crucial towards reducing the GHG emissions. This research also shed light on an innovative agricultural method, in comparison to traditional farming, that leads to sustainable agriculture in the long run. The biochar research is also a way to transfer research knowledge from laboratory to practical use.

**Keywords:** biochar, carbon sequestration, carbon storage, biomass, agriculture

The agricultural sector contributes to climate change problems through greenhouse gas (GHG) emission from various agricultural activities. However, the agricultural sector is also a carbon sink, both in terms of its potential to store carbon in various forms and its cultivated area, where agricultural areas are scattered all over the globe. Thus, agricultural areas could potentially be utilized as effective carbon sequestration areas. Moreover, the Food and Agriculture Organization (FAO) of the United Nations (UN) has also suggested the use of agricultural areas for carbon

According to the UN Framework Convention on Climate Change (UNFCCC), the measurement of GHG emission reduction and the measurement of carbon capture and storage in agricultural sectors should not have any effect on food production and farmers. The framework has been specially emphasized in agricultural and developing countries, where most of the population are farmers and are from a low socioeconomic background. Therefore, GHG reduction can be performed in the

Sequestration and Plant Biomass

#### **Chapter 3**

## Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass Enhancement Using Biochar

*Saowanee Wijitkosum and Thavivongse Sriburi*

### **Abstract**

The agricultural sector, especially in developing countries, is vulnerable to the effects of climate change partially caused by greenhouse gas (GHG) emissions from agricultural areas. Field crops are capable of bio-sequestration in its aboveground and belowground biomass. Incorporating biochar as a soil amendment increases its potential to become an important bio-sequestration which makes the agricultural sector a key contributor to climate change mitigation. This chapter discussed and presented data obtained from research on biochar using to increase plant biomass for carbon sequestration purposes. The biochar was produced from cassava stems by pyrolysis using a patented retort that was especially designed for agriculturalists to produce a low-cost biochar for their own use. The ability to increase biomass of field crops for carbon sequestration is crucial towards reducing the GHG emissions. This research also shed light on an innovative agricultural method, in comparison to traditional farming, that leads to sustainable agriculture in the long run. The biochar research is also a way to transfer research knowledge from laboratory to practical use.

**Keywords:** biochar, carbon sequestration, carbon storage, biomass, agriculture

#### **1. Introduction**

The agricultural sector contributes to climate change problems through greenhouse gas (GHG) emission from various agricultural activities. However, the agricultural sector is also a carbon sink, both in terms of its potential to store carbon in various forms and its cultivated area, where agricultural areas are scattered all over the globe. Thus, agricultural areas could potentially be utilized as effective carbon sequestration areas. Moreover, the Food and Agriculture Organization (FAO) of the United Nations (UN) has also suggested the use of agricultural areas for carbon sequestration to reduce GHG emissions [1, 2].

According to the UN Framework Convention on Climate Change (UNFCCC), the measurement of GHG emission reduction and the measurement of carbon capture and storage in agricultural sectors should not have any effect on food production and farmers. The framework has been specially emphasized in agricultural and developing countries, where most of the population are farmers and are from a low socioeconomic background. Therefore, GHG reduction can be performed in the form of a carbon sink in agricultural areas, where the carbon that is sequestered by biomass during photosynthesis or bio-sequestration [2, 3] can reduce the amount of GHG emission throughout the plant's life time [4–7]. Bio-sequestration appears to be a suitable and viable means of mitigation for long-term climate objectives. Many research reports have suggested that plants are capable of bio-sequestration in the form of accumulated biomass in their stems and in the soil [1, 6, 8]. The notion of carbon sequestration in biomass as a means to climate change mitigation is based upon the aim of storing carbon in different types of forest areas [9–13]. Although carbon sequestration in plant biomass in agriculture is an effective tool for climate change mitigation, carbon sequestration in agricultural sectors has not yet been intensively evaluated in agricultural countries. The level of carbon sequestration in the aboveground and belowground biomass of plants depends on the plant's biomass and thus varies with the plant species/cultivar, age, and quantity of the plants [14, 15]. Some or many field crop areas are suitable for carbon sequestration without negative impacts on farmers and food production.

Biochar is a highly stable substance that is high in fixed carbon. Incorporating it into agricultural soils has the potential to become an important means for GHG reduction. Biochar contributes to GHG reduction by retaining the carbon within the soils and within the plants or bio-sequestration [16–20]. Moreover, biochar has been widely used as a soil amendment to improve crop yields, in terms of the quantity and quality [21–24]. It also improves the physical, chemical, and biological characteristics of the soil [23, 25–28]. Therefore, using biochar as a soil amendment can help reduce requirements for agrochemical fertilizers, which is one of the causes of GHG emissions. It fits within the framework from the UNFCCC and Kyoto Protocol report [29, 30].

In this context, this chapter discussed and presented data obtained from research on biochar using to increase plant biomass for carbon sequestration purposes. The biochar was produced from feedstocks by pyrolysis using a patented retort that was especially designed for agriculturalists to produce a low-cost biochar for their own use. The biochar research is also a way to transfer research knowledge from laboratory to practical use.

#### **2. Biochar, carbon sequestration, and plant biomass relationships**

The indirect storage of carbon is the natural CO2 storage system from the growth of plants, which is an inexpensive method and can be implemented anywhere in the world. Most of the time, it is implemented in forested areas; however, according to a number of research studies, agricultural areas as well as forested areas are considered a promising place to store carbon [2, 4–7, 23]. It could reduce greenhouse gases as well as perform as a sink of agricultural CO2. Undoubtedly, the method is given considerable attention, especially by the Food and Agriculture Organization (FAO) who gives very much importance on measures to reduce greenhouse gases [31]. The movement of carbon and the variation scale of CO2 from air to soil increase carbon in soil. Subsequently, there is a decreasing amount of CO2 released from soil to air. Therefore, carbon storage is an influential mechanism that tremendously affects the reduction of greenhouse gases, which has approximately 89% of technical efficiency, whereas there was a 9% and 2% reduction of methane gas and nitrous oxide released from soil, respectively. Moreover, the movement of carbon from carbon emissions to carbon absorptions would efficiently reduce the variation of the atmosphere [32].

IPCC [1] characterized carbon storage in forested areas into five places including biomass above ground, underground biomass, dead trees, and organic carbon in the soil, all of which consist of storage in trees, and most of it is stored underground. Each

**37**

**Thailand**

**3.1 Study area**

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass…*

type of trees possesses different carbon storage efficiency and accumulated carbon according to the wood and types of wood changing according to the present related conditions [33–35], such as the age of the forest, the type of the forest, and the tree sizes [36], the forest density [37], the forest structure [38], and more. Nevertheless, plants except big trees can be adopted in storing carbon with more studies concerning the amount of carbon absorption or the amount of carbon storage in the life cycle of each plant. Carbon would be captured since the initial growth of plants until their full maturity. After plants are fully grown, the captured carbon would remain stable. Carbon indirect storage adopts photosynthesis of the plants, which depends on CO2 to propel the chemical reaction to water turning into glucose and oxygen, as in Eq. (1).

Carbon storage in the soil of agricultural and forested areas is an approach several countries have adopted to reduce GHG emissions. The implementation could be immediate and inexpensive, relying on the photosynthesis of plants that store carbon in the plant tissues (cores, leaves, fruits, and roots). After the death of these parts, these organic parts decompose, while it is also hard for some parts to decompose such as humus, which remain in the soil as organic matters. The number of the fallen plant components varies according to habitats of living organisms. The factors that affect the fallen plants include plant types, environment, the care of the plants, and duration. By and large, products obtained from the plants are more than fallen plants, possibly attributable to the plant age compared to the plant density [14]. According to that, biochar is adopted in the carbon storage in the soil in order to cut the cycle of being released to the atmosphere. Furthermore, methane and nitrous oxide emissions could be cut down from agricultural areas; hence, this

Biochar can improve the degraded soil, which has been proved by research to effectively enhance agricultural products, increasing the biomass of plants [23, 39–41], which is an indirect way to reduce greenhouse gases (Carbon Negative Technology) [17, 18, 42]. What is more, biochar has a high volume of fixed carbon. After the process of pyrolysis, there would be only 50% of carbon left in biochar [18, 44, 45]. Carbon in biochar is steady and hard to decompose by microorganisms in the soil, making biochar remain underground for a long time. Thus, this could be considered a way of carbon storage in the soil [20, 46], different from other organic matters such as plants, green manure, compost manure, and manure. These could decompose quickly, especially in tropical areas, giving rise to a high volume of CO2 emissions in a rapid manner [47]. For this reason, agricultural areas with the integration of biochar can store carbon more effectively than those with the integration of biomass with the same amount of carbon [48]. According to the research study by Maraseni [49], once there is a change in the agricultural areas from enlargement by deforestation and slash and burn systems to deforestation and slash and char systems, there is 12% reduction of losing carbon. Biochar made of grass could reduce 3 tons of CO2 emissions per 1 ton of biochar [50].

**3. Pilot project for biochar application for sustainable agriculture in** 

The study of increasing biomass in feeding maize (*Zea mays* L.) was performed on experimental plots in Pa Deng-Biochar Research Center (Pd-BRC), Pa Deng

C6H12O6 + 6O2 (1)

*DOI: http://dx.doi.org/10.5772/intechopen.82090*

6CO2 <sup>+</sup> 6H2O⎯⎯⟶ Sunlight energy

process is effective in greenhouse gas reduction.

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass… DOI: http://dx.doi.org/10.5772/intechopen.82090*

type of trees possesses different carbon storage efficiency and accumulated carbon according to the wood and types of wood changing according to the present related conditions [33–35], such as the age of the forest, the type of the forest, and the tree sizes [36], the forest density [37], the forest structure [38], and more. Nevertheless, plants except big trees can be adopted in storing carbon with more studies concerning the amount of carbon absorption or the amount of carbon storage in the life cycle of each plant. Carbon would be captured since the initial growth of plants until their full maturity. After plants are fully grown, the captured carbon would remain stable. Carbon indirect storage adopts photosynthesis of the plants, which depends on CO2 to propel the chemical reaction to water turning into glucose and oxygen, as in Eq. (1). 6CO2 <sup>+</sup> 6H2O⎯⎯⟶ Sunlight energy

$$\text{6CO}\_2 + \text{6H}\_2\text{O} \xrightarrow[\text{Sunlight energy}]{} \text{C}\_6\text{H}\_{12}\text{O}\_6 + \text{6O}\_2\tag{1}$$

Carbon storage in the soil of agricultural and forested areas is an approach several countries have adopted to reduce GHG emissions. The implementation could be immediate and inexpensive, relying on the photosynthesis of plants that store carbon in the plant tissues (cores, leaves, fruits, and roots). After the death of these parts, these organic parts decompose, while it is also hard for some parts to decompose such as humus, which remain in the soil as organic matters. The number of the fallen plant components varies according to habitats of living organisms. The factors that affect the fallen plants include plant types, environment, the care of the plants, and duration. By and large, products obtained from the plants are more than fallen plants, possibly attributable to the plant age compared to the plant density [14]. According to that, biochar is adopted in the carbon storage in the soil in order to cut the cycle of being released to the atmosphere. Furthermore, methane and nitrous oxide emissions could be cut down from agricultural areas; hence, this process is effective in greenhouse gas reduction.

Biochar can improve the degraded soil, which has been proved by research to effectively enhance agricultural products, increasing the biomass of plants [23, 39–41], which is an indirect way to reduce greenhouse gases (Carbon Negative Technology) [17, 18, 42]. What is more, biochar has a high volume of fixed carbon. After the process of pyrolysis, there would be only 50% of carbon left in biochar [18, 44, 45]. Carbon in biochar is steady and hard to decompose by microorganisms in the soil, making biochar remain underground for a long time. Thus, this could be considered a way of carbon storage in the soil [20, 46], different from other organic matters such as plants, green manure, compost manure, and manure. These could decompose quickly, especially in tropical areas, giving rise to a high volume of CO2 emissions in a rapid manner [47]. For this reason, agricultural areas with the integration of biochar can store carbon more effectively than those with the integration of biomass with the same amount of carbon [48]. According to the research study by Maraseni [49], once there is a change in the agricultural areas from enlargement by deforestation and slash and burn systems to deforestation and slash and char systems, there is 12% reduction of losing carbon. Biochar made of grass could reduce 3 tons of CO2 emissions per 1 ton of biochar [50].

#### **3. Pilot project for biochar application for sustainable agriculture in Thailand**

#### **3.1 Study area**

The study of increasing biomass in feeding maize (*Zea mays* L.) was performed on experimental plots in Pa Deng-Biochar Research Center (Pd-BRC), Pa Deng

*Biochar - An Imperative Amendment for Soil and the Environment*

without negative impacts on farmers and food production.

from laboratory to practical use.

form of a carbon sink in agricultural areas, where the carbon that is sequestered by biomass during photosynthesis or bio-sequestration [2, 3] can reduce the amount of GHG emission throughout the plant's life time [4–7]. Bio-sequestration appears to be a suitable and viable means of mitigation for long-term climate objectives. Many research reports have suggested that plants are capable of bio-sequestration in the form of accumulated biomass in their stems and in the soil [1, 6, 8]. The notion of carbon sequestration in biomass as a means to climate change mitigation is based upon the aim of storing carbon in different types of forest areas [9–13]. Although carbon sequestration in plant biomass in agriculture is an effective tool for climate change mitigation, carbon sequestration in agricultural sectors has not yet been intensively evaluated in agricultural countries. The level of carbon sequestration in the aboveground and belowground biomass of plants depends on the plant's biomass and thus varies with the plant species/cultivar, age, and quantity of the plants [14, 15]. Some or many field crop areas are suitable for carbon sequestration

Biochar is a highly stable substance that is high in fixed carbon. Incorporating it into agricultural soils has the potential to become an important means for GHG reduction. Biochar contributes to GHG reduction by retaining the carbon within the soils and within the plants or bio-sequestration [16–20]. Moreover, biochar has been widely used as a soil amendment to improve crop yields, in terms of the quantity and quality [21–24]. It also improves the physical, chemical, and biological characteristics of the soil [23, 25–28]. Therefore, using biochar as a soil amendment can help reduce requirements for agrochemical fertilizers, which is one of the causes of GHG emissions. It fits

within the framework from the UNFCCC and Kyoto Protocol report [29, 30]. In this context, this chapter discussed and presented data obtained from research on biochar using to increase plant biomass for carbon sequestration purposes. The biochar was produced from feedstocks by pyrolysis using a patented retort that was especially designed for agriculturalists to produce a low-cost biochar for their own use. The biochar research is also a way to transfer research knowledge

**2. Biochar, carbon sequestration, and plant biomass relationships**

The indirect storage of carbon is the natural CO2 storage system from the growth of plants, which is an inexpensive method and can be implemented anywhere in the world. Most of the time, it is implemented in forested areas; however, according to a number of research studies, agricultural areas as well as forested areas are considered a promising place to store carbon [2, 4–7, 23]. It could reduce greenhouse gases as well as perform as a sink of agricultural CO2. Undoubtedly, the method is given considerable attention, especially by the Food and Agriculture Organization (FAO) who gives very much importance on measures to reduce greenhouse gases [31]. The movement of carbon and the variation scale of CO2 from air to soil increase carbon in soil. Subsequently, there is a decreasing amount of CO2 released from soil to air. Therefore, carbon storage is an influential mechanism that tremendously affects the reduction of greenhouse gases, which has approximately 89% of technical efficiency, whereas there was a 9% and 2% reduction of methane gas and nitrous oxide released from soil, respectively. Moreover, the movement of carbon from carbon emissions to carbon absorptions would efficiently reduce the variation of

IPCC [1] characterized carbon storage in forested areas into five places including biomass above ground, underground biomass, dead trees, and organic carbon in the soil, all of which consist of storage in trees, and most of it is stored underground. Each

**36**

the atmosphere [32].

sub-district, Kaeng Krachan district, Petchaburi province, Thailand. This is part of the Huay Sai Royal Development Study Centre. The topology is undulating and rolling. The soil is sandy loam with a medium to high soil permeability, a medium to very low organic matter (OM = 0.04–1.16), and a pH that ranges from slightly alkaline to extremely acidic. The land has very low soil fertility and experiences soil erosion and water scarcity [51]. The majority of the area in Pa Deng is a slope complex with a gradient of more than 35%. Therefore, the Pa Deng area is enclosed by hills that limit the land utilization to only 12% of the total area [52]. The low soil fertility and limited area available for agriculture lead to the heavy use of agrochemicals among farmers to improve the quality and yield of their agricultural products. This creates long-term negative effects on the soil and environment.

#### **3.2 Research design and experimental plots**

A completely randomized design was used for this study. There were 7 treatments each with 4 replications giving a total of 16 experimental plots. Each experimental plot was 3 × 5 m in size. The maize was planted in two crop cycles. After harvesting the first cycle, the treatments were left in their original condition with no further addition of biochar or organic fertilizer. The maize was planted in May and was harvested in August. Pa Deng has been suffering from droughts for a long period of time. The crops were planted during the absence of rain period and in the strong sunlight. The crops were watered from water sprinklers.

There are seven treatments in total. Four treatments consisted of soil plus 5.6 ton/ ha of organic fertilizer with different amounts of added biochar at 0 (TBC0), 5 (TMBC0.5), 25 (TMBC2.5), and 30 (TMBC3.0) ton/ha, respectively. The other three treatments consisted of soil plus added biochar at 0, 5 (TBC0.5), 25 (TBC2.5), and 30 (TBC3.0) ton/ha, respectively. TBC0 was the controlled treatment.

The organic fertilizer used in this study was produced from the composting of soybean stems, and its characteristics were as follows: pH 8.3, electrical conductivity (EC) of 3.50 dS/m, 40.30 wt.% OM, 23.43 wt.% total organic carbon (TOC), 1.70 wt.% total nitrogen (total N), 0.87 wt.% total phosphorus (total P2O5), 3.54 wt.% total potassium (total K2O), and a 13.75 C/N ratio. In general, all the properties of fertilizer were shown in **Table 1**. The organic fertilizer used in this study was in accordance with all the parameters of the Organic Fertilizer Standard of the Thai Department of Agriculture in 2005 [53].

The maize used in this study was a single-cross hybrid CP 888 variety (flint corn) with strong stems. This maize can be waited for a long harvest. The maize is drought tolerant and can grow well in upland areas with medium precipitation making it suitable in the Pa Deng area. It is also popular among farmers. Biochemical pesticides and herbicides were used to prevent pests and weeds, especially during the period of 13–25 days after seeding emergence. This is the most critical period to prevent flora and pests from severely affecting the crops [53, 54].

#### **3.3 Biochar production and its characteristic**

Biochar was produced from cassava stems (cassava crop waste) by pyrolysis process using the Controlled Temperature Biochar Retort for Slow Pyrolysis Process (patented) that the research team invented to suit local uses. The biochar process is simple and low-cost [20, 23]. The retort was a controlled temperature biochar retort for slow pyrolysis which was complied with the standard set by FAO [56], with a controlled temperature between 450 and 600°C. After the process was finished, the biochar was ground and sieved to less than 3 mm diameter. This particle size was selected since it improves soil aeration and other processes in the soil [55, 57].

**39**

200.46 m2

**Table 1.**

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass…*

The biochar sampling method was adapted from the Standardized Product Definition and Product Testing Guidelines for Biochar that is used in soil [58] by collecting samples from every pyrolysis process. The samples were randomly selected from the ground biochar and analyzed for their specific surface area, total pore volume, average pore diameter, pH, EC, cation exchange capacity (CEC), OM, total carbon (C), total organic carbon (TOC), %hydrogen (H), %Oxygen (O), and

The cassava biochar composites were comprised of 58.46 wt.% total C and 58.46 wt.% TOC. The biochar from the cassava stems had a specific surface area of

with an alkaline pH of 9.6, EC of 1.35 dS/m, and CEC of 11.00 cmol/kg. The cassava biochar had a very high OM content of 25.89%, total N of 0.98%, total P2O5 of

The cassava stem biochar was high in carbon, mostly in the form of amorphous carbon in which the carbon atoms were attached in aromatic rings [18, 21, 22, 42, 44]. This chemical property makes the carbon in cassava stem biochar very stable [59–61] and creates a highly porous carbon structure in the biochar [60, 62]. The pyrolysis biochar at 450–600°C also contributed to the high stability of carbon [60, 63, 64]. The high porosity of biochar allows biochar to absorb and retain water and nutrients within the soil [23, 42, 55, 61, 65]. This helps with aeration and reduces soil density [18, 60, 66–68]. Moreover, the appropriate temperature during the pyrolysis process of the cassava stems also increased porosity on the biochar's surface which led to increased ions on the its surface [17, 18, 62, 69, 89]. This resulted in a high ion exchange capacity and high CEC [26, 42, 60, 69, 70]. As a result, the cassava stem biochar had a high capacity to retain and adsorb organic carbon and non-organic matters within the soil. Moreover, it also increased activities in the soil and ion exchange between nutrients in the form of soil solution. Cassava biochar has high alkalinity (pH 9.6). Alkalinity affects the type of biomass made into biochar [25, 71, 72]. Moreover, biochar from cassava stems also had a high OM (25.9 wt.%), which would contribute to an increased OM level in the soil and improve the soil fertility. These physical and chemical characteristics and chemical formations in biochar made it suitable as a soil amendment to increase plant growth [23, 25, 43, 44, 55, 60, 74, 75] and soil amelioration in acidic soils.

/g and average pore diameter of 24.4 Å,

the molar hydrogen to total organic carbon ratio (H/Corg Ratio).

/g, total pore volume of 0.12 cm3

*The properties of pre-experimental soil, fertilizer, and cassava biochar.*

0.82%, and total K2O of 1.68% (**Table 1**).

*DOI: http://dx.doi.org/10.5772/intechopen.82090*

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass… DOI: http://dx.doi.org/10.5772/intechopen.82090*


#### **Table 1.**

*Biochar - An Imperative Amendment for Soil and the Environment*

**3.2 Research design and experimental plots**

sub-district, Kaeng Krachan district, Petchaburi province, Thailand. This is part of the Huay Sai Royal Development Study Centre. The topology is undulating and rolling. The soil is sandy loam with a medium to high soil permeability, a medium to very low organic matter (OM = 0.04–1.16), and a pH that ranges from slightly alkaline to extremely acidic. The land has very low soil fertility and experiences soil erosion and water scarcity [51]. The majority of the area in Pa Deng is a slope complex with a gradient of more than 35%. Therefore, the Pa Deng area is enclosed by hills that limit the land utilization to only 12% of the total area [52]. The low soil fertility and limited area available for agriculture lead to the heavy use of agrochemicals among farmers to improve the quality and yield of their agricultural products. This creates long-term negative effects on the soil and environment.

A completely randomized design was used for this study. There were 7 treatments each with 4 replications giving a total of 16 experimental plots. Each experimental plot was 3 × 5 m in size. The maize was planted in two crop cycles. After harvesting the first cycle, the treatments were left in their original condition with no further addition of biochar or organic fertilizer. The maize was planted in May and was harvested in August. Pa Deng has been suffering from droughts for a long period of time. The crops were planted during the absence of rain period and in the

There are seven treatments in total. Four treatments consisted of soil plus 5.6 ton/

The organic fertilizer used in this study was produced from the composting of soybean stems, and its characteristics were as follows: pH 8.3, electrical conductivity (EC) of 3.50 dS/m, 40.30 wt.% OM, 23.43 wt.% total organic carbon (TOC), 1.70 wt.% total nitrogen (total N), 0.87 wt.% total phosphorus (total P2O5), 3.54 wt.% total potassium (total K2O), and a 13.75 C/N ratio. In general, all the properties of fertilizer were shown in **Table 1**. The organic fertilizer used in this study was in accordance with all the parameters of the Organic Fertilizer Standard

The maize used in this study was a single-cross hybrid CP 888 variety (flint corn) with strong stems. This maize can be waited for a long harvest. The maize is drought tolerant and can grow well in upland areas with medium precipitation making it suitable in the Pa Deng area. It is also popular among farmers. Biochemical pesticides and herbicides were used to prevent pests and weeds, especially during the period of 13–25 days after seeding emergence. This is the most critical period to prevent flora and pests from severely affecting the crops [53, 54].

Biochar was produced from cassava stems (cassava crop waste) by pyrolysis process using the Controlled Temperature Biochar Retort for Slow Pyrolysis Process (patented) that the research team invented to suit local uses. The biochar process is simple and low-cost [20, 23]. The retort was a controlled temperature biochar retort for slow pyrolysis which was complied with the standard set by FAO [56], with a controlled temperature between 450 and 600°C. After the process was finished, the biochar was ground and sieved to less than 3 mm diameter. This particle size was selected since it improves soil aeration and other processes in the soil [55, 57].

ha of organic fertilizer with different amounts of added biochar at 0 (TBC0), 5 (TMBC0.5), 25 (TMBC2.5), and 30 (TMBC3.0) ton/ha, respectively. The other three treatments consisted of soil plus added biochar at 0, 5 (TBC0.5), 25 (TBC2.5), and

strong sunlight. The crops were watered from water sprinklers.

of the Thai Department of Agriculture in 2005 [53].

**3.3 Biochar production and its characteristic**

30 (TBC3.0) ton/ha, respectively. TBC0 was the controlled treatment.

**38**

*The properties of pre-experimental soil, fertilizer, and cassava biochar.*

The biochar sampling method was adapted from the Standardized Product Definition and Product Testing Guidelines for Biochar that is used in soil [58] by collecting samples from every pyrolysis process. The samples were randomly selected from the ground biochar and analyzed for their specific surface area, total pore volume, average pore diameter, pH, EC, cation exchange capacity (CEC), OM, total carbon (C), total organic carbon (TOC), %hydrogen (H), %Oxygen (O), and the molar hydrogen to total organic carbon ratio (H/Corg Ratio).

The cassava biochar composites were comprised of 58.46 wt.% total C and 58.46 wt.% TOC. The biochar from the cassava stems had a specific surface area of 200.46 m2 /g, total pore volume of 0.12 cm3 /g and average pore diameter of 24.4 Å, with an alkaline pH of 9.6, EC of 1.35 dS/m, and CEC of 11.00 cmol/kg. The cassava biochar had a very high OM content of 25.89%, total N of 0.98%, total P2O5 of 0.82%, and total K2O of 1.68% (**Table 1**).

The cassava stem biochar was high in carbon, mostly in the form of amorphous carbon in which the carbon atoms were attached in aromatic rings [18, 21, 22, 42, 44]. This chemical property makes the carbon in cassava stem biochar very stable [59–61] and creates a highly porous carbon structure in the biochar [60, 62]. The pyrolysis biochar at 450–600°C also contributed to the high stability of carbon [60, 63, 64]. The high porosity of biochar allows biochar to absorb and retain water and nutrients within the soil [23, 42, 55, 61, 65]. This helps with aeration and reduces soil density [18, 60, 66–68]. Moreover, the appropriate temperature during the pyrolysis process of the cassava stems also increased porosity on the biochar's surface which led to increased ions on the its surface [17, 18, 62, 69, 89]. This resulted in a high ion exchange capacity and high CEC [26, 42, 60, 69, 70]. As a result, the cassava stem biochar had a high capacity to retain and adsorb organic carbon and non-organic matters within the soil. Moreover, it also increased activities in the soil and ion exchange between nutrients in the form of soil solution.

Cassava biochar has high alkalinity (pH 9.6). Alkalinity affects the type of biomass made into biochar [25, 71, 72]. Moreover, biochar from cassava stems also had a high OM (25.9 wt.%), which would contribute to an increased OM level in the soil and improve the soil fertility. These physical and chemical characteristics and chemical formations in biochar made it suitable as a soil amendment to increase plant growth [23, 25, 43, 44, 55, 60, 74, 75] and soil amelioration in acidic soils.

#### **3.4 Soil properties and soil character analysis**

The soil in the experimental plots was analyzed before planting the crops. Soil was selected at random from areas scattered throughout each plot and taken from 0 to 30 cm depth. The samples were considered as composite samples in the soil analysis. Physical and chemical characteristics of the soil samplings were analyzed using the methods developed by the Soil Survey Staff [76], including the pH, OM (Walkley and Black method), soil texture (hydrometer method), CEC (leaching method), EC, total N (Kjeldahl method), available phosphorus (avail. P) (Bray II determine by spectrophotometer), and exchangeable potassium (exch. K) (ammonium acetate extraction determine by atomic absorption spectrophotometer).

The pre-experimental soil analysis results (**Table 1**) revealed that the soil in the experimental plots was a slightly alkaline sandy clay loam (%Sand = 57.0, %Silt = 22.5, %Clay = 20.5) with a pH of 6.95 and EC of 0.08 dS/m. It is suitable for growing flint corn for feeding animals [53]. The soil had a high level of primary macronutrients except total N (total N = 0.09%, avail. P = 21.80 mg/kg, and exch. K = 215.75 mg/kg) (**Table 1**).

The soil in this region had a very low fertility with an OM of 1.32%. The OM in soils is decomposed by soil microbes, and it depended on the carbon distribution at different soil densities, which helped prevent the decomposition [77].

#### **3.5 Evaluation of the maize biomass**

During the harvesting period, the maize was uprooted from the soil and washed with water. The plants were then left to dry in the shade before being measured for their whole plant fresh (wet) weight (FW). The plants were then cut so as to separate the roots, upper roots (stems + leaves + staminate), pods, and seeds. The FW of each part of the plant was measured then cut into small pieces and put in an oven at 70°C for 48 h or until the weight was stable (dry weight: DW). Using the FW/DW ratio, the crop biomass was estimated. After that, the DW of the plants was used to derive the moisture content (wt.%), from which the biomass in different parts of the crop in each experimental plot was calculated, derived from Eqs. (2) and (3):

$$\text{Biomass} = \text{100 } \left[ \text{DW (g)} \right] / \left( \text{moisture content} \star \text{100} \right) \tag{2}$$

$$\text{Moisture content} = 100 \, \text{[FW (g) - DW (g)]} / \text{[FW (g)]} \tag{3}$$

#### **3.6 Analysis of carbon sequestration from maize grown in the different biochar-supplemented soils**

The amount of carbon sequestered in each part of maize in the different experimental treatment plots consisted of the carbon concentration of the plant biomass, as shown in Eq. (4). The plant carbon stock was estimated by multiplying the total plant biomass with the carbon concentration (%). This study applied the FAO method [78] for carbon stock in biomass, derived from Eqs. (4) and (5):

$$\text{Biomass C} = \begin{bmatrix} \text{Carbon concentration (\%)} \ge \text{biomass} \end{bmatrix} / 100 \tag{4}$$

$$\text{Biomass } \mathbf{C\_{stock}} \text{ = } \text{Biomass } \mathbf{C\_{ay}} + \text{Biomass } \mathbf{C\_{by}} \tag{5}$$

**41**

**Figure 1.**

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass…*

Biomass Cstock total is the total stock of C in the biomass from every part of maize. The constituents of the biomass carbon stock aboveground were the carbon content in the upper roots, corn cobs, and seeds, while belowground they were the carbon

All the data collected from the different experiments and field samples during the study were compiled and processed for statistical analysis by analysis of variances (ANOVA). Comparisons between means were tested for significance with Tukey's multiple comparison test using the Statistical Package of the Social Science

Biomass assessment during the first crop cycle (CC1) (**Figure 1**) indicated that the total biomass in the maize grown in TMBC3.0 was the highest (17.63 ton/ha), while the biomass was lowest (14.71 ton/ha) in the soil added fertilizer (TBC0). However, these numerical differences in the total biomass were not significant among all seven soil types. Comparing the results between biochar-incorporated treatments, it was apparent that the amount of biomass increased in relation to the amount of added biochar (highest in TBC3.0 and lowest in TBC0.5) and increased further if the fertilizer was also added. However, soil incorporated with fertilizer and the least amount of biochar (TMBC0.5) yielded less biomass than soil incorporated with solely biochar at the highest amount (TBC3.0), but again these differ-

Maize biomass in the second crop (CC2) yielded (**Figure 1**) similar results to those of CC1, where numerically the highest total biomass was found in TMBC3.0, both in the whole plant (17.31 ton/ha) and in each part of the maize. Compared to the control, the total biomass and biomass of roots in TMC3.0 treatment showed significant results whereas the other ones did not. Even though there was no significant difference in biomass (total and each plant part) among soil types, which may reflect the low sample size relative to the level of intra-sample variation,

*Total biomass in the maize grown in soil supplemented with different biochar levels for two successive crop cycles. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly different (p < 0.05).*

(SPSS) software. Significance was accepted at the p < 0.05 level.

ences were not statistically significant (**Figure 1**).

**3.7 Biomass of maize grown in the different biochar-supplemented soils**

*DOI: http://dx.doi.org/10.5772/intechopen.82090*

content in the roots.

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass… DOI: http://dx.doi.org/10.5772/intechopen.82090*

Biomass Cstock total is the total stock of C in the biomass from every part of maize. The constituents of the biomass carbon stock aboveground were the carbon content in the upper roots, corn cobs, and seeds, while belowground they were the carbon content in the roots.

All the data collected from the different experiments and field samples during the study were compiled and processed for statistical analysis by analysis of variances (ANOVA). Comparisons between means were tested for significance with Tukey's multiple comparison test using the Statistical Package of the Social Science (SPSS) software. Significance was accepted at the p < 0.05 level.

#### **3.7 Biomass of maize grown in the different biochar-supplemented soils**

Biomass assessment during the first crop cycle (CC1) (**Figure 1**) indicated that the total biomass in the maize grown in TMBC3.0 was the highest (17.63 ton/ha), while the biomass was lowest (14.71 ton/ha) in the soil added fertilizer (TBC0). However, these numerical differences in the total biomass were not significant among all seven soil types. Comparing the results between biochar-incorporated treatments, it was apparent that the amount of biomass increased in relation to the amount of added biochar (highest in TBC3.0 and lowest in TBC0.5) and increased further if the fertilizer was also added. However, soil incorporated with fertilizer and the least amount of biochar (TMBC0.5) yielded less biomass than soil incorporated with solely biochar at the highest amount (TBC3.0), but again these differences were not statistically significant (**Figure 1**).

Maize biomass in the second crop (CC2) yielded (**Figure 1**) similar results to those of CC1, where numerically the highest total biomass was found in TMBC3.0, both in the whole plant (17.31 ton/ha) and in each part of the maize. Compared to the control, the total biomass and biomass of roots in TMC3.0 treatment showed significant results whereas the other ones did not. Even though there was no significant difference in biomass (total and each plant part) among soil types, which may reflect the low sample size relative to the level of intra-sample variation,

#### **Figure 1.**

*Biochar - An Imperative Amendment for Soil and the Environment*

The soil in the experimental plots was analyzed before planting the crops. Soil was selected at random from areas scattered throughout each plot and taken from 0 to 30 cm depth. The samples were considered as composite samples in the soil analysis. Physical and chemical characteristics of the soil samplings were analyzed using the methods developed by the Soil Survey Staff [76], including the pH, OM (Walkley and Black method), soil texture (hydrometer method), CEC (leaching method), EC, total N (Kjeldahl method), available phosphorus (avail. P) (Bray II determine by spectrophotometer), and exchangeable potassium (exch. K) (ammonium acetate extraction determine by atomic absorption spectrophotometer). The pre-experimental soil analysis results (**Table 1**) revealed that the soil in the experimental plots was a slightly alkaline sandy clay loam (%Sand = 57.0, %Silt = 22.5, %Clay = 20.5) with a pH of 6.95 and EC of 0.08 dS/m. It is suitable for growing flint corn for feeding animals [53]. The soil had a high level of primary macronutrients except total N (total N = 0.09%, avail. P = 21.80 mg/kg, and exch.

The soil in this region had a very low fertility with an OM of 1.32%. The OM in soils is decomposed by soil microbes, and it depended on the carbon distribution at

During the harvesting period, the maize was uprooted from the soil and washed with water. The plants were then left to dry in the shade before being measured for their whole plant fresh (wet) weight (FW). The plants were then cut so as to separate the roots, upper roots (stems + leaves + staminate), pods, and seeds. The FW of each part of the plant was measured then cut into small pieces and put in an oven at 70°C for 48 h or until the weight was stable (dry weight: DW). Using the FW/DW ratio, the crop biomass was estimated. After that, the DW of the plants was used to derive the moisture content (wt.%), from which the biomass in different parts of the crop in each experimental plot was calculated, derived from Eqs. (2) and (3):

Biomass = 100 [DW (g)]/(moisture content + 100) (2)

Moisture content = 100 [FW (g) − DW (g)]/FW (g) (3)

The amount of carbon sequestered in each part of maize in the different experimental treatment plots consisted of the carbon concentration of the plant biomass, as shown in Eq. (4). The plant carbon stock was estimated by multiplying the total plant biomass with the carbon concentration (%). This study applied the FAO method [78] for carbon stock in biomass, derived from Eqs. (4) and (5):

Biomass C = [Carbon concentration (%) x biomass]/100 (4)

Biomass Cstock total = Biomass Cag + Biomass Cbg (5)

**3.6 Analysis of carbon sequestration from maize grown in the different** 

different soil densities, which helped prevent the decomposition [77].

**3.4 Soil properties and soil character analysis**

K = 215.75 mg/kg) (**Table 1**).

**3.5 Evaluation of the maize biomass**

**biochar-supplemented soils**

**40**

*Total biomass in the maize grown in soil supplemented with different biochar levels for two successive crop cycles. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly different (p < 0.05).*

numerically it was apparent that incorporating the appropriate amount of biochar within the soil could increase the amount of biomass in every part of the maize.

Comparing between the two successive crop cycles (**Figure 2**), the amount of biomass found in each treatment in CC2 was less than in CC1, except for the roots in TBC2.5, TBC3.0, TMBC2.5, and TMBC3.0 that had a slightly higher biomass (0.061, 0.049, 0.120, and 0.125 ton/ha, respectively) in CC2 than in CC1. However, TMBC3.0, which received the highest amount of biochar plus fertilizer, had the least difference between the two crop cycles (−0.317 ton/ha) that the total biomass in the maize grown in TMBC3.0 was the highest in both crop cycles, while TBC0 (control) had the highest difference between the two crop cycles (−2.13 ton/ha). Thus, increasing the level of biochar in the soil (within this range of 5 to 3 ton/ha) numerically decreased the loss of biomass yield between the first and second successive cultivation. However, none of these numerical differences were statistically significant.

From the results, considering only the maize seed biomass that can be sold for animal feed, adding the fertilizer with highest amount of biochar into the soil gave the highest (yield) weight of maize seeds in both the first and second maize plantations, and adding only biochar into the soil gave a higher maize seed biomass in both crop cycles than that obtained when only adding fertilizer to the soil. The weight of maize seed biomass from TMB3.0 was the highest (6.280 ton/ha in CC1 and 6.149 ton/ha in CC2), while the results reported by Wijitkosum [55] revealed that TMB2.5 (13 cobs) had the highest average number of cobs per plant from 8 sample plants per treatment followed by TMB3.0 (12 cobs). In the second crop, the soil amendment with biochar and fertilizer still gave a high yield of maize seeds with only a small decrease in the biomass compared to that in the first crop cycle.

The increase of maize biomass obtained from the soil with added biochar reflects the high porosity, surface area, and ion exchange capacity of biochar [20, 21, 23, 44, 61, 62]. In addition, the highly aromatic chemical structure of

#### **Figure 2.**

*Biomass in each part of the maize grown in soil supplemented with different biochar levels for two successive crop cycles. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly different (p < 0.05).*

**43**

**Figure 3.**

*different (p < 0.05).*

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass…*

biochar leads to a high chance of oxidation reactions to form functional groups, and so biochar has many anions on its surface and hence a high ion exchange capacity [20, 42, 44, 65, 72, 73]. Moreover, biochar has many micropores that can absorb nutrients and anions from the soil solution [46, 59–62, 65, 79, 80] and to reduce

The organic matter, important as a source of nutrients for maize growth, mostly came from the added fertilizer and some from the biochar and soil. Together, they support the growth of the roots and aid in absorbing more nutrients and transfer to the stem. The root biomass was increased in every soil amendment with biochar alone or with biochar and fertilizer, at all levels of biochar, and was higher than that obtained in the soil with only fertilizer added. This result gave the consistent with many studies (e.g. [20, 60, 72, 81, 82]) indicating that biochar could also contribute to the suitable environment for the growth of plant root. In the second maize plantation, the root biomass was significantly higher in all the biochar treatments, and especially for the addition of fertilizer with the highest level of biochar, than

When the plant's roots grow well, they can absorb nutrients and water to build

The carbon stock in biomass in CC1 showed that the highest amount of carbon stored in biomass in TMBC3.0 at 7.22 ton/ha, while the lowest in TBC0 at 5.83 ton/ha

increased depending on the amount biochar added into the soil, especially when the biochar was added with the fertilizer. However, the carbon storage obtained with the

*The amount of carbon stored in maize. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly* 

(**Figure 3**). The study showed that the carbon storage in maize biomass was

up the biomass in other parts of the plant. For example, potassium affects the growth, photosynthesis, carbohydrate synthesis, and leaf and seed formation [83–86]. Calcium affects the strength of the maize plant and activates development of the roots and leaves, as well as controlling the soil's pH [20, 87]. Biochar produced from cassava has a high nutrient content, reflected in the observation that maize grows well with a higher biomass when grown in soil with added fertilizer and biochar or added biochar compared to that in soil with only added fertilizer.

nutrient leaching and provide a sustainable release to the plants.

that obtained from the soil with only fertilizer added.

**3.8 The amount of carbon sequestered from growing maize**

*DOI: http://dx.doi.org/10.5772/intechopen.82090*

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass… DOI: http://dx.doi.org/10.5772/intechopen.82090*

biochar leads to a high chance of oxidation reactions to form functional groups, and so biochar has many anions on its surface and hence a high ion exchange capacity [20, 42, 44, 65, 72, 73]. Moreover, biochar has many micropores that can absorb nutrients and anions from the soil solution [46, 59–62, 65, 79, 80] and to reduce nutrient leaching and provide a sustainable release to the plants.

The organic matter, important as a source of nutrients for maize growth, mostly came from the added fertilizer and some from the biochar and soil. Together, they support the growth of the roots and aid in absorbing more nutrients and transfer to the stem. The root biomass was increased in every soil amendment with biochar alone or with biochar and fertilizer, at all levels of biochar, and was higher than that obtained in the soil with only fertilizer added. This result gave the consistent with many studies (e.g. [20, 60, 72, 81, 82]) indicating that biochar could also contribute to the suitable environment for the growth of plant root. In the second maize plantation, the root biomass was significantly higher in all the biochar treatments, and especially for the addition of fertilizer with the highest level of biochar, than that obtained from the soil with only fertilizer added.

When the plant's roots grow well, they can absorb nutrients and water to build up the biomass in other parts of the plant. For example, potassium affects the growth, photosynthesis, carbohydrate synthesis, and leaf and seed formation [83–86]. Calcium affects the strength of the maize plant and activates development of the roots and leaves, as well as controlling the soil's pH [20, 87]. Biochar produced from cassava has a high nutrient content, reflected in the observation that maize grows well with a higher biomass when grown in soil with added fertilizer and biochar or added biochar compared to that in soil with only added fertilizer.

#### **3.8 The amount of carbon sequestered from growing maize**

The carbon stock in biomass in CC1 showed that the highest amount of carbon stored in biomass in TMBC3.0 at 7.22 ton/ha, while the lowest in TBC0 at 5.83 ton/ha (**Figure 3**). The study showed that the carbon storage in maize biomass was increased depending on the amount biochar added into the soil, especially when the biochar was added with the fertilizer. However, the carbon storage obtained with the

#### **Figure 3.**

*Biochar - An Imperative Amendment for Soil and the Environment*

numerically it was apparent that incorporating the appropriate amount of biochar within the soil could increase the amount of biomass in every part of the maize. Comparing between the two successive crop cycles (**Figure 2**), the amount of biomass found in each treatment in CC2 was less than in CC1, except for the roots in TBC2.5, TBC3.0, TMBC2.5, and TMBC3.0 that had a slightly higher biomass (0.061, 0.049, 0.120, and 0.125 ton/ha, respectively) in CC2 than in CC1. However, TMBC3.0, which received the highest amount of biochar plus fertilizer, had the least difference between the two crop cycles (−0.317 ton/ha) that the total biomass in the maize grown in TMBC3.0 was the highest in both crop cycles, while TBC0 (control) had the highest difference between the two crop cycles (−2.13 ton/ha). Thus, increasing the level of biochar in the soil (within this range of 5 to 3 ton/ha) numerically decreased the loss of biomass yield between the first and second successive cultivation. However, none of these numerical differences were statistically significant. From the results, considering only the maize seed biomass that can be sold for animal feed, adding the fertilizer with highest amount of biochar into the soil gave the highest (yield) weight of maize seeds in both the first and second maize plantations, and adding only biochar into the soil gave a higher maize seed biomass in both crop cycles than that obtained when only adding fertilizer to the soil. The weight of maize seed biomass from TMB3.0 was the highest (6.280 ton/ha in CC1 and 6.149 ton/ha in CC2), while the results reported by Wijitkosum [55] revealed that TMB2.5 (13 cobs) had the highest average number of cobs per plant from 8 sample plants per treatment followed by TMB3.0 (12 cobs). In the second crop, the soil amendment with biochar and fertilizer still gave a high yield of maize seeds with only a small decrease in the biomass compared to that in the first crop cycle. The increase of maize biomass obtained from the soil with added biochar reflects the high porosity, surface area, and ion exchange capacity of biochar [20, 21, 23, 44, 61, 62]. In addition, the highly aromatic chemical structure of

*Biomass in each part of the maize grown in soil supplemented with different biochar levels for two successive crop cycles. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly different (p < 0.05).*

**42**

**Figure 2.**

*The amount of carbon stored in maize. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly different (p < 0.05).*

lowest ratio of biochar with fertilizer (TMB0.5) was lower than that in the biochar only treatment when sufficient biochar was added (TBC2.5 and TBC3.0). Carbon storage in each part of the maize and the total amount of carbon storage were not significantly different among the seven treatments. The highest percentage of carbon storage in the maize biomass was found in the upper roots (46.72–49.21%), followed by that in the seeds (33.71–35.69%), corncobs (8.32–9.27%), and roots (8.04–9.10%) (**Figures 4** and **5**).

With respect to the results from the CC2 (**Figure 3**), TMBC3.0 still gave the highest carbon storage (7.46 ton/ha), followed by TMBC2.5, TBC3.0, TBC2.5, TMBC0.5, TBC0.5, and TBC0. The amount of carbon storage was clearly different among the soil treatments, especially with the addition of fertilizer plus a high level of biochar which resulted in a significantly higher amount of carbon storage than the addition of fertilizer alone, which is the standard agricultural soil amendment used by farmers. Soil amendment with fertilizer and a sufficient amount of biochar (TMBC2.5 and TMBC3.0) resulted in significantly higher root carbon storage than the addition of only fertilizer to the soil. Similarly, the ratio of carbon storage in the other parts of the maize plants was in the same pattern as that seen in the first crop (**Figures 4** and **5**), being highest in the upper roots (46.50–48.21%), then the seeds (35.39–37.49%), corncobs (6.64–8.27%), and roots (7.57–9.55%).

With respect to the amount of carbon storage between the first and second maize plantings, the total carbon storage on maize was increased only in the soil treatments with sufficient biochar addition alone or with the fertilizer adding sufficient biochar. Treatment TMB3.0 gave the highest amount of carbon storage in maize (+0.235 ton/ha), followed by TBC3.0 (+0.094 ton/ha), TBC2.5 (+0.083 ton/ha), and TMBC2.5 (+0.076 ton/ha. In contrast, soil amendment without any biochar, but with the fertilizer only (TBC0), resulted in the highest level of decreased carbon storage (−0.551 ton/ha) between the two maize planting cycles.

#### **Figure 4.**

*The percentage of carbon storage in different parts of maize. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly different (p < 0.05).*

**45**

second crop.

**Figure 5.**

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass…*

Considering the rate of total carbon change in maize biomass, the use of fertilizer (5.6 ton/ha) and biochar (30 ton/ha) (TMBC3.0) increased the amount of carbon storage in the maize biomass compared to that in the first crop cycle by 3.25%. The use of fertilizer alone (TBC0) or biochar alone showed a 9.45% or 2.28% decrease, respectively, in the total carbon storage in the second maize crop, whereas the soil amendment with fertilizer plus the lowest amount of biochar (TMBC0.5) gave only a 1.32% decrease in the total carbon storage in the maize biomass in the

*The amount of carbon stored in different parts of maize. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a* 

Adding the appropriate amount of biochar into the soil promotes plant growth [23, 25, 55], especially the roots stems, leaves, stamen, and corn stalk, leading to an increased plant biomass. Moreover, the presence of biochar in the soil promotes the plant growth and productivity even without soil amendment with fertilizer because biochar is organic carbon that cannot be easily digested by soil microorganisms [17, 42, 59–61, 88]. Although the soil mixed with fertilizer initially provides sufficient nutrients for maize growth, this may be insufficient in the longer term for successive crops due to the rapid microbial degradation and leaching of the nutrients, leading to the requirement for continual reapplication of fertilizer every crop cycle. To help restore the soluble nutrients and reduce their leaching from soil, [21, 41, 45, 46, 89–91], especially in tropical regions where the soil has a low organic matter and high washout rate, the biochar with the fertilizer was applied. Under these conditions, adding organic matter alone to tropical soil is not stable in the long term because the soil has a low anion exchange capacity, and so much of soluble fertilizer is washed out before being absorbed by plant roots. Instead, the requirement to continuously add a high amount of organic matter to the soil increases the production cost and decreases the soil quality and environment in the long term [47, 57, 92, 94–95]. In contrast, when adding biochar with the fertilizer into the soil, the biochar helps improve both the physical and chemical properties of the soil allowing the plant's roots to absorb the nutrients over a longer time period [20, 42, 43, 60],

*DOI: http://dx.doi.org/10.5772/intechopen.82090*

*different letter are significantly different (p < 0.05).*

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass… DOI: http://dx.doi.org/10.5772/intechopen.82090*

#### **Figure 5.**

*Biochar - An Imperative Amendment for Soil and the Environment*

(8.04–9.10%) (**Figures 4** and **5**).

planting cycles.

lowest ratio of biochar with fertilizer (TMB0.5) was lower than that in the biochar only treatment when sufficient biochar was added (TBC2.5 and TBC3.0). Carbon storage in each part of the maize and the total amount of carbon storage were not significantly different among the seven treatments. The highest percentage of carbon storage in the maize biomass was found in the upper roots (46.72–49.21%), followed by that in the seeds (33.71–35.69%), corncobs (8.32–9.27%), and roots

With respect to the results from the CC2 (**Figure 3**), TMBC3.0 still gave the highest carbon storage (7.46 ton/ha), followed by TMBC2.5, TBC3.0, TBC2.5, TMBC0.5, TBC0.5, and TBC0. The amount of carbon storage was clearly different among the soil treatments, especially with the addition of fertilizer plus a high level of biochar which resulted in a significantly higher amount of carbon storage than the addition of fertilizer alone, which is the standard agricultural soil amendment used by farmers. Soil amendment with fertilizer and a sufficient amount of biochar (TMBC2.5 and TMBC3.0) resulted in significantly higher root carbon storage than the addition of only fertilizer to the soil. Similarly, the ratio of carbon storage in the other parts of the maize plants was in the same pattern as that seen in the first crop (**Figures 4** and **5**), being highest in the upper roots (46.50–48.21%), then the seeds

With respect to the amount of carbon storage between the first and second maize plantings, the total carbon storage on maize was increased only in the soil treatments with sufficient biochar addition alone or with the fertilizer adding sufficient biochar. Treatment TMB3.0 gave the highest amount of carbon storage in maize (+0.235 ton/ha), followed by TBC3.0 (+0.094 ton/ha), TBC2.5 (+0.083 ton/ha), and TMBC2.5 (+0.076 ton/ha. In contrast, soil amendment without any biochar, but with the fertilizer only (TBC0), resulted in the highest level of decreased carbon storage (−0.551 ton/ha) between the two maize

*The percentage of carbon storage in different parts of maize. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a* 

(35.39–37.49%), corncobs (6.64–8.27%), and roots (7.57–9.55%).

**44**

**Figure 4.**

*different letter are significantly different (p < 0.05).*

*The amount of carbon stored in different parts of maize. CC1 and CC2 are the first and second crop cycles, respectively. Data are shown as the mean ± 1SD, derived from \*\* independent samples. Means within a row (small letter), or within a column (capital letter) between CC1 and CC2 of a given maize part, with a different letter are significantly different (p < 0.05).*

Considering the rate of total carbon change in maize biomass, the use of fertilizer (5.6 ton/ha) and biochar (30 ton/ha) (TMBC3.0) increased the amount of carbon storage in the maize biomass compared to that in the first crop cycle by 3.25%. The use of fertilizer alone (TBC0) or biochar alone showed a 9.45% or 2.28% decrease, respectively, in the total carbon storage in the second maize crop, whereas the soil amendment with fertilizer plus the lowest amount of biochar (TMBC0.5) gave only a 1.32% decrease in the total carbon storage in the maize biomass in the second crop.

Adding the appropriate amount of biochar into the soil promotes plant growth [23, 25, 55], especially the roots stems, leaves, stamen, and corn stalk, leading to an increased plant biomass. Moreover, the presence of biochar in the soil promotes the plant growth and productivity even without soil amendment with fertilizer because biochar is organic carbon that cannot be easily digested by soil microorganisms [17, 42, 59–61, 88]. Although the soil mixed with fertilizer initially provides sufficient nutrients for maize growth, this may be insufficient in the longer term for successive crops due to the rapid microbial degradation and leaching of the nutrients, leading to the requirement for continual reapplication of fertilizer every crop cycle. To help restore the soluble nutrients and reduce their leaching from soil, [21, 41, 45, 46, 89–91], especially in tropical regions where the soil has a low organic matter and high washout rate, the biochar with the fertilizer was applied. Under these conditions, adding organic matter alone to tropical soil is not stable in the long term because the soil has a low anion exchange capacity, and so much of soluble fertilizer is washed out before being absorbed by plant roots. Instead, the requirement to continuously add a high amount of organic matter to the soil increases the production cost and decreases the soil quality and environment in the long term [47, 57, 92, 94–95]. In contrast, when adding biochar with the fertilizer into the soil, the biochar helps improve both the physical and chemical properties of the soil allowing the plant's roots to absorb the nutrients over a longer time period [20, 42, 43, 60],

and so the maize received enough nutrients continuously leading to higher productivities. Thus, the total biomass of the maize in second plantation in TMBC3.0 and TMBC2.5 had decreased by less than 10%.

#### **4. Impact of biochar on biomass, bio-sequestration, and carbon sequestration**

The massive and deep rooting systems in annual crops allow for direct movement of C into the soil and make it less available for removal by harvest [96]. Therefore, the results suggested that the incorporation of the appropriate amount of biochar into soil may help increase the amount of biomass in the maize. These results are in accordance with other biochar research, where the appropriate amount of biochar induced chemical reactions within the soil which enhanced the quantity and quality of the crops [23, 25, 28, 57, 98–100]. Incorporating biochar with the fertilizer could enhance and sustain the biomass gain from the fertilizer addition. Moreover, biochar remains in the soil for a long period of time with less leaching, and so it is not necessary to add more biochar every new crop cycle. The result from the main component (70–90% by weight) of biochar is amorphous carbon [23, 25, 43, 59] arranged in aromatic rings that are highly stable in the soil for long times [21, 22, 43, 59, 61]. Moreover, other important qualities of biochar are its high density of micropores, high surface area, and high ion exchange capacity. Therefore, biochar has good soil amendment qualities and can increase the agricultural productivity in terms of both the quality and quantity of crop obtained [10, 17, 20, 23, 25, 27, 28, 62, 91, 93, 97, 99].

The amount of biomass has a direct effect on the amount of carbon stored in the biomass. The quantity of biomass is an important source of replenishing organic carbon in the soil. The potential for soils to sequester C depends on the rate of biomass production relative to that exported, such as by microbial activity [96, 100]. The treatments that resulted in a high maize biomass also had a high amount of carbon in their biomass. Using biochar in agricultural areas had a positive impact on the maize and increased the amount of biomass stored in every part of the maize (roots, stems, leaves, tassels, seeds, and corncobs), as reported previously [23]. This is because the characteristics of biochar are beneficial for plants and its ability to be used for soil amelioration [70, 71, 101, 102].

The structure of biochar is amorphous, in the form of aromatic hydrocarbons bound with oxygenated functional groups, which influences its high stability characteristic [18–22, 42–44, 49, 70]. Moreover, its highly porous structure contains a large amount of micropores with a high surface area giving a high adsorption capacity for cations [65, 70, 72, 73, 75, 89–91, 99]. Therefore, incorporating biochar within the soil in agricultural areas benefits the soil ecosystem and the physical, biological, and chemical characteristics of the soil [17, 18, 22, 23, 25–28, 62, 73, 79, 80, 101, 102]. The soil becomes more fertile, which in turn leads to higher maize productivity. Maize grown in biochar-incorporated soils had a higher amount of carbon stored in every part of the plant.

#### **5. Conclusion**

A single application of biochar to the soil used for maize plantations significantly increased the carbon storage in the plants (biomass quantity and amount of carbon in the biomass) even in the second crop. The amount of carbon storage was further increased when the fertilizer was also added with the biochar to the soil.

**47**

provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

1 Environmental Research Institute, Chulalongkorn University, Bangkok, Thailand

\* and Thavivongse Sriburi<sup>2</sup>

2 Chula UNISEARCH, Chulalongkorn University, Bangkok, Thailand

\*Address all correspondence to: w.m.saowanee@gmail.com

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass…*

The amount of plant biomass depends on the completion of plant growth, which is affected by the soil richness and nutrient availability. Adding organic material helps to improve the soil qualities and accelerate plant growth, but, especially in tropical soils, it can be washed out easily. The addition of biochar into the soil directly improves the physical and chemical properties of the soil, promotes microorganism activities and reduces nutrient leaching, and so leads to better plant growth and a

Carbon is stored in the soil directly by adding biochar, with its high stable carbon content, and will indirectly be the increased plant biomass. This is hence a method to reduce the carbon dioxide, a GHG emission, in agricultural areas and so help to mitigate climate change. This study revealed that adding a high amount of biochar together with fertilizer to agricultural soil only once is sufficient for at least two crops of maize and so would not only increase carbon storage in plants, but also the reduced fertilizer application will further reduce GHG release in agricultural

This research was supported by the "Minimizing GHG Emissions from Industrial and Agricultural Sectors to Reduce Adverse Impacts of Climate Change in Thailand, Sub Project: Reducing GHG Emission from Agricultural Sector by Using Biochar" funded by the 2014 In-depth Strategic Research Fund, Ratchadapisek Sompoch Endowment Fund, Chulalongkorn University. Furthermore, this chapter was also partially supported by "Building a Smart Community for Climate Change and Natural Disasters Adaptation. Sub-project: Using biochar in urban farming areas for food security and carbon sequestration on high-rise buildings" (CU59- 002-IC), the 2016 Ratchadapisek Sompoch Endowment Fund for in-depth high

*DOI: http://dx.doi.org/10.5772/intechopen.82090*

higher biomass in the long term.

**Acknowledgements**

potential research projects.

**Author details**

Saowanee Wijitkosum1

areas and also reduce the production cost for farmers.

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass… DOI: http://dx.doi.org/10.5772/intechopen.82090*

The amount of plant biomass depends on the completion of plant growth, which is affected by the soil richness and nutrient availability. Adding organic material helps to improve the soil qualities and accelerate plant growth, but, especially in tropical soils, it can be washed out easily. The addition of biochar into the soil directly improves the physical and chemical properties of the soil, promotes microorganism activities and reduces nutrient leaching, and so leads to better plant growth and a higher biomass in the long term.

Carbon is stored in the soil directly by adding biochar, with its high stable carbon content, and will indirectly be the increased plant biomass. This is hence a method to reduce the carbon dioxide, a GHG emission, in agricultural areas and so help to mitigate climate change. This study revealed that adding a high amount of biochar together with fertilizer to agricultural soil only once is sufficient for at least two crops of maize and so would not only increase carbon storage in plants, but also the reduced fertilizer application will further reduce GHG release in agricultural areas and also reduce the production cost for farmers.

#### **Acknowledgements**

*Biochar - An Imperative Amendment for Soil and the Environment*

TMBC2.5 had decreased by less than 10%.

20, 23, 25, 27, 28, 62, 91, 93, 97, 99].

amelioration [70, 71, 101, 102].

carbon stored in every part of the plant.

**sequestration**

and so the maize received enough nutrients continuously leading to higher productivities. Thus, the total biomass of the maize in second plantation in TMBC3.0 and

The massive and deep rooting systems in annual crops allow for direct movement of C into the soil and make it less available for removal by harvest [96]. Therefore, the results suggested that the incorporation of the appropriate amount of biochar into soil may help increase the amount of biomass in the maize. These results are in accordance with other biochar research, where the appropriate amount of biochar induced chemical reactions within the soil which enhanced the quantity and quality of the crops [23, 25, 28, 57, 98–100]. Incorporating biochar with the fertilizer could enhance and sustain the biomass gain from the fertilizer addition. Moreover, biochar remains in the soil for a long period of time with less leaching, and so it is not necessary to add more biochar every new crop cycle. The result from the main component (70–90% by weight) of biochar is amorphous carbon [23, 25, 43, 59] arranged in aromatic rings that are highly stable in the soil for long times [21, 22, 43, 59, 61]. Moreover, other important qualities of biochar are its high density of micropores, high surface area, and high ion exchange capacity. Therefore, biochar has good soil amendment qualities and can increase the agricultural productivity in terms of both the quality and quantity of crop obtained [10, 17,

The amount of biomass has a direct effect on the amount of carbon stored in the biomass. The quantity of biomass is an important source of replenishing organic carbon in the soil. The potential for soils to sequester C depends on the rate of biomass production relative to that exported, such as by microbial activity [96, 100]. The treatments that resulted in a high maize biomass also had a high amount of carbon in their biomass. Using biochar in agricultural areas had a positive impact on the maize and increased the amount of biomass stored in every part of the maize (roots, stems, leaves, tassels, seeds, and corncobs), as reported previously [23]. This is because the characteristics of biochar are beneficial for plants and its ability to be used for soil

The structure of biochar is amorphous, in the form of aromatic hydrocarbons bound with oxygenated functional groups, which influences its high stability characteristic [18–22, 42–44, 49, 70]. Moreover, its highly porous structure contains a large amount of micropores with a high surface area giving a high adsorption capacity for cations [65, 70, 72, 73, 75, 89–91, 99]. Therefore, incorporating biochar within the soil in agricultural areas benefits the soil ecosystem and the physical, biological, and chemical characteristics of the soil [17, 18, 22, 23, 25–28, 62, 73, 79, 80, 101, 102]. The soil becomes more fertile, which in turn leads to higher maize productivity. Maize grown in biochar-incorporated soils had a higher amount of

A single application of biochar to the soil used for maize plantations significantly increased the carbon storage in the plants (biomass quantity and amount of carbon in the biomass) even in the second crop. The amount of carbon storage was further increased when the fertilizer was also added with the biochar to the soil.

**4. Impact of biochar on biomass, bio-sequestration, and carbon** 

**46**

**5. Conclusion**

This research was supported by the "Minimizing GHG Emissions from Industrial and Agricultural Sectors to Reduce Adverse Impacts of Climate Change in Thailand, Sub Project: Reducing GHG Emission from Agricultural Sector by Using Biochar" funded by the 2014 In-depth Strategic Research Fund, Ratchadapisek Sompoch Endowment Fund, Chulalongkorn University. Furthermore, this chapter was also partially supported by "Building a Smart Community for Climate Change and Natural Disasters Adaptation. Sub-project: Using biochar in urban farming areas for food security and carbon sequestration on high-rise buildings" (CU59- 002-IC), the 2016 Ratchadapisek Sompoch Endowment Fund for in-depth high potential research projects.

#### **Author details**

Saowanee Wijitkosum1 \* and Thavivongse Sriburi<sup>2</sup>

1 Environmental Research Institute, Chulalongkorn University, Bangkok, Thailand

2 Chula UNISEARCH, Chulalongkorn University, Bangkok, Thailand

\*Address all correspondence to: w.m.saowanee@gmail.com

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[72] Zhang J, Liu J, Liu R. Effects of pyrolysis temperature and heating time on biochar obtained from the pyrolysis of straw and lignosulfonate. Bioresource Technology. 2015;**176**:288-291

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*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass…*

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Research. 2010;**48**(7):516-525

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Pearson; 2002. 960 p

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[91] Liang B, Lehmann J, Solomon D, Kinyangi J, Grossman J, O'Neill B, et al. Black carbon increases cation exchange capacity in soils. Soil Science Society of America Journal. 2006;**70**:1719-1730

[92] Brady NC, Weil RR. The Nature and Properties of Soils. 13th ed. New Jersey:

[93] Schulz, H. and Glaser, B. Effects of biochar compared to organic and inorganic fertilizers on soil quality and plant growth in a greenhouse experiment. Journal of Plant Nutrition and Soil Science. 2012;**175**(3):410-422

[94] Sparkes J, Stoutjesdijk P. Biochar:

Productivity. ABARES Technical Report 11.6, Canberra, Australia. Australian Bureau of Agricultural and Resource Economics and Sciences; 2011

[95] Tiessen H, Cuevas E, Chacon P. The role of soil organic matter in sustaining soil fertility. Nature. 1994;**371**:783-785

[96] Lemus R, Lal R. Bioenergy crops and carbon sequestration. Critical Reviews in Plant Sciences. 2005;**24**:

[97] Major J, Rondon M, Molina D, Riha SJ, Lehmann J. Maize yield and nutrition during 4 years after biochar application

1-21

Implications for Agricultural

AL. Characterisation and evaluation of biochars for their application as a soil amendment. Australian Journal of Soil

[89] Chan KY, Van Zwieten L, Meszaros I, Downie A, Joseph S. Agronomic values of greenwaste biochar as a soil amendment. Australian Journal of Soil

*DOI: http://dx.doi.org/10.5772/intechopen.82090*

[79] Schulz, H., Dunst, G. and Glaser, B. Positive effects of composted biochar on plant growth and soil fertility. Agronomy for Sustainable Development. 2013;**33**(4):817-827

[80] Kloss S, Zehetner F, Dellantonio A, Hamid R, Ottner F, Liedtke V, et al. Characterization of slow pyrolysis biochars: Effects of feedstocks and pyrolysis temperature on biochar properties. Journal of Environmental

Quality. 2012;**41**:990-1000

[81] Khodake SP, Borale R, Petare RK. Ichthyofaunal diversity in Jamkhedi reservoir in Dhule district of Maharashtra, India. Journal of Environmental Research and Development. 2014;**9**(1):177-183

[82] Manoj B. Bio-processing of Indian coals by micro-organisms: An investigation. Journal of Environmental

Research and Development.

[83] Armstrong DL. Potassium for agriculture. Better Crops with Plant

[84] De Datta SK. Mineral and fertilizer management of rice. In: De Datta SK, Principles and Practices of Rice Production. New York: John Wiley;

[85] Hartt CE. Effects of potassium deficiency upon translocation of 14C in attached blades and entire plants of sugarcane. Plant Physiology.

[86] Johnston A, Steen I. Understanding Potassium and Its Use in Agriculture.

Manufacturers Association; 2003. 40 p

Brussels: European Fertilizer

[87] Korb N, Jones C, Jacobsen J. Potassium Cycling, Testing, and Fertilizer Recommendations. Nutrient Management Module Number 5. Montana: Montana state University Extension Service; 2005. 12 p

2014;**9**(1):209-215

Food. 1998;**82**:4-5

1981. p. 348-419

1969;**44**:1461-1469

*Increasing the Amount of Biomass in Field Crops for Carbon Sequestration and Plant Biomass… DOI: http://dx.doi.org/10.5772/intechopen.82090*

[79] Schulz, H., Dunst, G. and Glaser, B. Positive effects of composted biochar on plant growth and soil fertility. Agronomy for Sustainable Development. 2013;**33**(4):817-827

*Biochar - An Imperative Amendment for Soil and the Environment*

[71] Liu L, Shen G, Sun M, Cao X, Shang G, Chen P. Effect of biochar on nitrous oxide emission and its potential mechanisms. Journal of the Air and Waste Management Association.

[72] Zhang J, Liu J, Liu R. Effects of pyrolysis temperature and heating time on biochar obtained from the pyrolysis of straw and lignosulfonate. Bioresource

Technology. 2015;**176**:288-291

[73] Steiner C. Slash and char as alternative to slash and burn - Soil charcoal amendments maintain soil fertility and establish a carbon sink [thesis]. Bayreuth: University of

[74] Basso B, Fiorentino C, Cammarano D, Cafiero G, Dardanelli J. Analysis of rainfall distribution on spatial and temporal patterns of wheat yield in Mediterranean environment. European Journal of Agronomy. 2012;**41**:52-65

[75] Laird DA, Fleming PD, Karlen DL, Wang B, Horton R. Biochar impact on nutrient leaching from a Midwestern

[76] Soil Survey Staff. Soil survey field and laboratory methods manual. Soil survey investigations report No. 51, Version 2.0. In: Burt, R, Soil Survey Staff, editors. Washington, DC: US Government Printing Office; 2014

[77] Bouajila A, Gallali T. Soil organic carbon fractions and aggregate stability in carbonated and no carbonated soils in Tunisia. Journal of Agronomy.

[78] Ponce-Hernandez R, Koohafkan P, Antoine J. Assessing Carbon Stocks and Modelling Win-Win Scenarios of Carbon Sequestration through Land-Use Changes. Rome: Food and Agricultural Organization of the United Nations;

agricultural soil. Geoderma.

2010;**158**:436-442

2008;**7**:127-137

2004

2014;**64**:894-902

Bayreuth; 2007

[63] Steinbeiss S, Gleixner G, Antonietti M. Effect of biochar amendment on soil carbon balance and soil microbial activity. Soil Biology and Biochemistry.

[64] Sun Y, Gao B, Yao Y, Fang J, Zhang M, Zhou Y, et al. Effects of feedstock type, production method, and pyrolysis temperature on biochar and hydrochar properties. Chemical Engineering.

[65] Atkinson C, Fitzgerald J, Hipps N. Potential mechanisms for achieving agricultural benefits from biochar application to temperate soils: A review.

[66] Jones BEH, Haynes RJ, Phillips IR. Effect of amendment of bauxite processing sand with organic

materials on its chemical, physical and microbial properties. Environmental Management. 2010;**91**:2281-2288

[67] Bhogal A, Nicholson FA, Chambers BJ. Organic carbon additions: Effects on soil bio-physical and physico-chemical properties. European Journal of Soil

[68] Hati KM, Swarup A, Dwivedi AK, Misra AK, Bandyopadhyay KK. Changes in soil physical properties and organic carbon status at the topsoil horizon of a vertisol of central India after 28 years of continuous cropping, fertilization and manuring. Agriculture, Ecosystems and

Environment. 2007;**119**:127-134

Cycles. 2000;**14**:777-793

[70] Amonette JE, Joseph S. Characteristics of biochar:

J, Joseph S, editors. Biochar for Environmental Management: Science and Technology. London: Earthscan;

[69] Schmidt MW, Noack AG. Black carbon in soils and sediments: Analysis, distribution, implications and current challenges. Global Biogeochemical

Microchemical properties. In: Lehmann

Plant and Soil. 2010;**337**:1-18

Science. 2009;**60**:276-286

2009;**41**:130-1310

2014;**240**:574-578

**52**

2009. pp. 33-52

[80] Kloss S, Zehetner F, Dellantonio A, Hamid R, Ottner F, Liedtke V, et al. Characterization of slow pyrolysis biochars: Effects of feedstocks and pyrolysis temperature on biochar properties. Journal of Environmental Quality. 2012;**41**:990-1000

[81] Khodake SP, Borale R, Petare RK. Ichthyofaunal diversity in Jamkhedi reservoir in Dhule district of Maharashtra, India. Journal of Environmental Research and Development. 2014;**9**(1):177-183

[82] Manoj B. Bio-processing of Indian coals by micro-organisms: An investigation. Journal of Environmental Research and Development. 2014;**9**(1):209-215

[83] Armstrong DL. Potassium for agriculture. Better Crops with Plant Food. 1998;**82**:4-5

[84] De Datta SK. Mineral and fertilizer management of rice. In: De Datta SK, Principles and Practices of Rice Production. New York: John Wiley; 1981. p. 348-419

[85] Hartt CE. Effects of potassium deficiency upon translocation of 14C in attached blades and entire plants of sugarcane. Plant Physiology. 1969;**44**:1461-1469

[86] Johnston A, Steen I. Understanding Potassium and Its Use in Agriculture. Brussels: European Fertilizer Manufacturers Association; 2003. 40 p

[87] Korb N, Jones C, Jacobsen J. Potassium Cycling, Testing, and Fertilizer Recommendations. Nutrient Management Module Number 5. Montana: Montana state University Extension Service; 2005. 12 p

[88] Singh B, Singh BP, Cowie AL. Characterisation and evaluation of biochars for their application as a soil amendment. Australian Journal of Soil Research. 2010;**48**(7):516-525

[89] Chan KY, Van Zwieten L, Meszaros I, Downie A, Joseph S. Agronomic values of greenwaste biochar as a soil amendment. Australian Journal of Soil Research. 2007;**45**(8):629

[90] Lehmann J. Biological carbon sequestration must and can be a win-win approach. Climatic Change. 2009;**97**(3):459-463

[91] Liang B, Lehmann J, Solomon D, Kinyangi J, Grossman J, O'Neill B, et al. Black carbon increases cation exchange capacity in soils. Soil Science Society of America Journal. 2006;**70**:1719-1730

[92] Brady NC, Weil RR. The Nature and Properties of Soils. 13th ed. New Jersey: Pearson; 2002. 960 p

[93] Schulz, H. and Glaser, B. Effects of biochar compared to organic and inorganic fertilizers on soil quality and plant growth in a greenhouse experiment. Journal of Plant Nutrition and Soil Science. 2012;**175**(3):410-422

[94] Sparkes J, Stoutjesdijk P. Biochar: Implications for Agricultural Productivity. ABARES Technical Report 11.6, Canberra, Australia. Australian Bureau of Agricultural and Resource Economics and Sciences; 2011

[95] Tiessen H, Cuevas E, Chacon P. The role of soil organic matter in sustaining soil fertility. Nature. 1994;**371**:783-785

[96] Lemus R, Lal R. Bioenergy crops and carbon sequestration. Critical Reviews in Plant Sciences. 2005;**24**: 1-21

[97] Major J, Rondon M, Molina D, Riha SJ, Lehmann J. Maize yield and nutrition during 4 years after biochar application

to a Colombian savanna oxisol. Plant and Soil. 2010;**333**:117-128

[98] Butnan S, Deenik JL, Toomsan B, Antal MJ, Vityakon P. Biochar properties influencing greenhouse gas emissions in tropical soils differing in texture and mineralogy. Journal of Environmental Quality. 2016;**45**:1509-1519

[99] Asai H, Samson BK, Stephan HM, Songyikhangsuthor K, Homma K, Kiyono Y, et al. Biochar amendment techniques for upland rice production in Northern Laos 1. Soil physical properties, leaf SPAD and grain yield. Field Crops Research. 2009;**111**(1):81-84

[100] Williams RJ, Hutley LB, Cook GD, Russell-Smith J, Edwards A, Chen X. Assessing the carbon sequestration potential of mesic savannas in the Northern Territory, Australia: Approaches, uncertainties and potential impacts of fire. Functional Plant Biology. 2004;**31**:415-422

[101] Ibrahim H, Hatira A, Gallali T. Relationship between nitrogen and soil properties: Using multiple linear regressions and structural equation modelling. International Journal of Research and Reviews. 2013;**2**:1-7

[102] Mašek O, Brownsort PA. Research on Production of Bespoke Biochar. Poster Presented at the 2nd UK Biochar Research Centre Conference; 28-29 October 2010; United Kingdom. UKBRC: Rothamsted; 2010

**55**

**Chapter 4**

**Abstract**

heavy metals

**1. Introduction**

Influence of Sewage Sludge

Growth, and Heavy Metals

*Yin Wang, Cheng Yu, Futian You, Xiaoda Tang,* 

of HMs, which is very important for their utilization in barren soil.

due to the problem of pathogens and contaminants [4].

**Keywords:** sewage sludge biochar, soil, Chinese cabbage, microbial environment,

Because of rapid economic development, more than 30 million tons of wet sewage sludge (SS) are produced in China every year [1]. SS contains lots of organic pollutants, microorganisms, eggs of parasitic organisms, and heavy metals (HMs), which makes it an obvious threat to ecological environment [2]. Conventional disposal technologies such as landfill, incineration, and agricultural application encounter many environmental problems; so, they cannot be widely used [3]. Especially, the direct application of SS in agricultural production is strictly banned

*Guangwei Yu, Shengyu Xie, Jianli Ma, Xiaofu Shang,* 

*Héctor U. Levatti, Lanjia Pan, Jie Li and Chunxing Li*

The effects of sewage sludge biochar (SSB) on the microbial environment, Chinese cabbage yield, and heavy metals (HMs) availability of soil were comprehensively investigated in this study. Results showed that the concentrations of the dehydrogenase (DHA) and urease in the soil added with 10% SSB were 3.60 and 1.67 times as high as that of the control soil, respectively, after planting; the concentrations of the bacteria, fungi, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) in the soil added with 10% SSB after planting reached 2.84, 2.62, 1.76, and 2.23 times, respectively, compared with those of the control group; the weights of the aboveground and underground parts of Chinese cabbage were 5.82 and 8.67 times as high as those of the control group, respectively. Moreover, the addition of SSB enhanced the immobilization of Cr, Ni, and Cd. All in all, SSB can improve the microbial environment of soil and inhibit the availability

Environment, Chinese Cabbage

Biochar on the Microbial

Availability of Soil

#### **Chapter 4**

*Biochar - An Imperative Amendment for Soil and the Environment*

to a Colombian savanna oxisol. Plant

[98] Butnan S, Deenik JL, Toomsan B, Antal MJ, Vityakon P. Biochar properties influencing greenhouse gas emissions in tropical soils differing in texture and mineralogy. Journal of Environmental

[99] Asai H, Samson BK, Stephan HM, Songyikhangsuthor K, Homma K, Kiyono Y, et al. Biochar amendment techniques for upland rice production in Northern Laos 1. Soil physical properties, leaf SPAD and grain yield. Field Crops Research. 2009;**111**(1):81-84

[100] Williams RJ, Hutley LB, Cook GD, Russell-Smith J, Edwards A, Chen X. Assessing the carbon sequestration

potential of mesic savannas in the Northern Territory, Australia: Approaches, uncertainties and potential

impacts of fire. Functional Plant

[101] Ibrahim H, Hatira A, Gallali T. Relationship between nitrogen and soil properties: Using multiple linear regressions and structural equation modelling. International Journal of Research and Reviews. 2013;**2**:1-7

[102] Mašek O, Brownsort PA. Research on Production of Bespoke Biochar. Poster Presented at the 2nd UK Biochar Research Centre Conference; 28-29 October 2010; United Kingdom. UKBRC: Rothamsted; 2010

Biology. 2004;**31**:415-422

and Soil. 2010;**333**:117-128

Quality. 2016;**45**:1509-1519

**54**

## Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth, and Heavy Metals Availability of Soil

*Guangwei Yu, Shengyu Xie, Jianli Ma, Xiaofu Shang, Yin Wang, Cheng Yu, Futian You, Xiaoda Tang, Héctor U. Levatti, Lanjia Pan, Jie Li and Chunxing Li*

#### **Abstract**

The effects of sewage sludge biochar (SSB) on the microbial environment, Chinese cabbage yield, and heavy metals (HMs) availability of soil were comprehensively investigated in this study. Results showed that the concentrations of the dehydrogenase (DHA) and urease in the soil added with 10% SSB were 3.60 and 1.67 times as high as that of the control soil, respectively, after planting; the concentrations of the bacteria, fungi, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) in the soil added with 10% SSB after planting reached 2.84, 2.62, 1.76, and 2.23 times, respectively, compared with those of the control group; the weights of the aboveground and underground parts of Chinese cabbage were 5.82 and 8.67 times as high as those of the control group, respectively. Moreover, the addition of SSB enhanced the immobilization of Cr, Ni, and Cd. All in all, SSB can improve the microbial environment of soil and inhibit the availability of HMs, which is very important for their utilization in barren soil.

**Keywords:** sewage sludge biochar, soil, Chinese cabbage, microbial environment, heavy metals

#### **1. Introduction**

Because of rapid economic development, more than 30 million tons of wet sewage sludge (SS) are produced in China every year [1]. SS contains lots of organic pollutants, microorganisms, eggs of parasitic organisms, and heavy metals (HMs), which makes it an obvious threat to ecological environment [2]. Conventional disposal technologies such as landfill, incineration, and agricultural application encounter many environmental problems; so, they cannot be widely used [3]. Especially, the direct application of SS in agricultural production is strictly banned due to the problem of pathogens and contaminants [4].

The pyrolysis of SS is a technology in which SS is heated under zero or lowoxygen condition to produce sewage sludge biochar (SSB) and pyrolysis oil and gas. After conversion into SSB, all the pathogens and organic pollutants in SS are eliminated and the volume of SS is significantly reduced [5]. Also, the oil and gas produced by pyrolysis can save the input of external energy as supplemental fuel [6]. Apart from the applications mentioned above, SSB has numerous special advantages in improving soil quality and crop growth. First of all, biochar possesses a porous structure that can influence the soil's structure, porosity, particle size distribution, and density, which contributes to increasing the soil water-holding capacity and microbial activity [7]. Furthermore, biochar is alkaline and can improve the pH of soil [8]. Finally, biochar is rich in plenty of nutrients such as nitrogen, phosphorus, potassium, etc., exhibiting a positive effect on plant growth [9]. Song et al. [10] studied the influence of pyrolysis temperature and proportion of SSB on garlic yield and HMs accumulation and found that the SSB produced at 450°C and its addition at 25% could improve the yield of garlic well and inhibit HMs accumulation in garlic. Khan et al. [4] investigated the effects of SSB on rice yield, HMs bioaccumulation, and greenhouse gas emission and found that SSB amendments increased the pH, total nitrogen, organic carbon, and available nutrients of soil and crop yield, and decreased HMs bioavailability and N2O emission. In addition, there are a large amount of studies on the influence of SSB on plant growth and HMs migration that have proved the positive effects of biochar addition [11–13].

Based on the pilot-scale plant on pyrolysis of SS with capacity 30 t/d in Xiamen, and our previous studies, it was found that the HMs in SS were converted into a more stable state after hydrothermal pretreatment combined with pyrolysis and the obtained SSB could be used to prepare ceramsite [14–16]. However, the study of the influence of SSB from the pyrolysis of hydrothermally treated SS on the microbial environment of soil during planting is still indispensable. On the one hand, the soil microorganisms are involved in many biochemical processes, including the degradation and conversion of organic matter, the mineralization and immobilization of nutrients, and the formation and stabilization of soil aggregates [17]. On the other hand, the soil microorganisms are also a repository of soil nutrients and an important nutrition source for plant growth [18]. In this study, we chose the common and easy-to-grow Chinese cabbage as the planting crop to investigate the influence of SSB from the pyrolysis of hydrothermally treated SS on the physical and chemical properties and microbial environment of soil before and after planting. Furthermore, the growth status of Chinese cabbage and HMs availability were also studied.

#### **2. Materials and methods**

#### **2.1 Materials**

The used soil was collected from a farmland near an abandoned mine in Longyan, Fujian Province, China. The soil was sieved and homogenized after collection. SS was obtained from a wastewater treatment plant in Xiamen, China. Then, the SS was disposed via hydrothermal treatment at 160°C for 1 hour, and followed by filtration and pyrolysis by a rotary furnace at 500°C for 3 hours to obtain SSB in the pilot-scale plant in Xiamen, Fujian Province [19]. The high-quality and early raping NO.5 seed of Chinese cabbage was chosen as the testing plant.

#### **2.2 Chinese cabbage pot experiment**

The Chinese cabbage pot experiment was carried out in a greenhouse located in Xiamen, Fujian province, China (24.36 N–118.3 E) and the height and diameter of

**57**

**Table 1.**

*RT-PCR amplification primers.*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth…*

the polyethylene pot were 15 and 20 cm, respectively. To investigate the influence of SSB on the properties of soil, Chinese cabbage growth, and HMs availability, SSB was added with an SSB-to-soil mass ratio of 1:9 (10% SSB) in pot and the pure soil served as a control group. The total weight of soil or treated soil in each pot was 5.0 kg. Every pot experiment was assessed by four replicates. After seeding, each pot was treated with watering regularly and thinned out to ensure that only one Chinese cabbage grows. When the pot experiment finished (about 55 days), the soil

The pH was measured according to the agricultural trade standard of China (NY/T 1377-2007) and the solution was analyzed with a UB-7 pH meter (Ultra Basic, US). Electrical conductivity (EC) was measured according to the national environmental protection standard of China (HJ 802-2016) and the solution was analyzed with a Cond 3110 conductometer (Teltracon 325, Germany). Surface area was calculated by the Brunauer-Emmett-Teller (BET) method after testing using nitrogen adsorption/desorption isotherms with an apparatus (TriStar II 3020 V1.01, USA). Elemental analysis was conducted by an elemental analyzer (Vario MAX, Germany). The concentrations of nutrient elements were analyzed by digestion in an acid mixture [15] and the solution was determined by ICP-OES (Optima 7000DV, USA). The concentrations of available HMs in the sample were measured by the DTPA extraction method [20] and the solution was determined by ICP-MS (Agilent 7500cx, USA). The surface functional group of SSB was analyzed by FTIR spectrometry (iS10, Thermo, USA) and the morphology of SSB was analyzed by

The dehydrogenase (DHA) activity in soil was measured by the triphenyltetrazolium chloride (TTC) spectrophotometric method [21]. The urease activity was measured by Nesslerization [22]. The molecular target genes of bacteria, fungi, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) were measured by quantitative real-time polymerase chain reaction (RT-PCR) analysis [23] and the information of primers is shown in **Table 1**. A standard curve was obtained by tenfold dilution of recombinant plasmid acquired in each molecular target gene of the above microorganisms and each sample was repeated three times. The SYBR® Premix Ex Taq™ kit from Bao Biological Engineering (Dalian, China) Co. Ltd. was used for analysis at Roche Lightcycler® 480 PCR. The quantitative PCR reaction system was 20 μL, including 1 μL of tenfold diluted DNA template, 10 μL of SYBR® Premix Ex Taq™, 0.2 μL (20 μM) of forward and reverse primers

ATTCCGCGGCTGCTGGCA 517R

TCCTCCGCTTATTGATATGC ITS4

GCGGCCATCCATCTGTATGT Arch-amoAR

CCCCTCKGSAAAGCCTTCTTC amoA-2R

and Chinese cabbage were collected to conduct relative tests, respectively.

scanning electron microscopy (SEM, S-4800, Hitachi, Japan).

**Target gene Primer name Primer sequence (5′–3′)** Bacteria 16S rRNA 58F CCTACGGGAGGCAGCAG

Fungi 18S iRNA ITS3 GCATCGATGAAGAACGCAGC

AOA amoA Arch-amoAF STAATGGTCTGGCTTAGACG

AOB amoA amoA-1F GGGGTTTCTACTGGTGGT

*DOI: http://dx.doi.org/10.5772/intechopen.82091*

**2.3 Analysis methods**

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth… DOI: http://dx.doi.org/10.5772/intechopen.82091*

the polyethylene pot were 15 and 20 cm, respectively. To investigate the influence of SSB on the properties of soil, Chinese cabbage growth, and HMs availability, SSB was added with an SSB-to-soil mass ratio of 1:9 (10% SSB) in pot and the pure soil served as a control group. The total weight of soil or treated soil in each pot was 5.0 kg. Every pot experiment was assessed by four replicates. After seeding, each pot was treated with watering regularly and thinned out to ensure that only one Chinese cabbage grows. When the pot experiment finished (about 55 days), the soil and Chinese cabbage were collected to conduct relative tests, respectively.

#### **2.3 Analysis methods**

*Biochar - An Imperative Amendment for Soil and the Environment*

have proved the positive effects of biochar addition [11–13].

Based on the pilot-scale plant on pyrolysis of SS with capacity 30 t/d in Xiamen, and our previous studies, it was found that the HMs in SS were converted into a more stable state after hydrothermal pretreatment combined with pyrolysis and the obtained SSB could be used to prepare ceramsite [14–16]. However, the study of the influence of SSB from the pyrolysis of hydrothermally treated SS on the microbial environment of soil during planting is still indispensable. On the one hand, the soil microorganisms are involved in many biochemical processes, including the degradation and conversion of organic matter, the mineralization and immobilization of nutrients, and the formation and stabilization of soil aggregates [17]. On the other hand, the soil microorganisms are also a repository of soil nutrients and an important nutrition source for plant growth [18]. In this study, we chose the common and easy-to-grow Chinese cabbage as the planting crop to investigate the influence of SSB from the pyrolysis of hydrothermally treated SS on the physical and chemical properties and microbial environment of soil before and after planting. Furthermore, the

growth status of Chinese cabbage and HMs availability were also studied.

The used soil was collected from a farmland near an abandoned mine in Longyan, Fujian Province, China. The soil was sieved and homogenized after collection. SS was obtained from a wastewater treatment plant in Xiamen, China. Then, the SS was disposed via hydrothermal treatment at 160°C for 1 hour, and followed by filtration and pyrolysis by a rotary furnace at 500°C for 3 hours to obtain SSB in the pilot-scale plant in Xiamen, Fujian Province [19]. The high-quality and

early raping NO.5 seed of Chinese cabbage was chosen as the testing plant.

The Chinese cabbage pot experiment was carried out in a greenhouse located in Xiamen, Fujian province, China (24.36 N–118.3 E) and the height and diameter of

The pyrolysis of SS is a technology in which SS is heated under zero or lowoxygen condition to produce sewage sludge biochar (SSB) and pyrolysis oil and gas. After conversion into SSB, all the pathogens and organic pollutants in SS are eliminated and the volume of SS is significantly reduced [5]. Also, the oil and gas produced by pyrolysis can save the input of external energy as supplemental fuel [6]. Apart from the applications mentioned above, SSB has numerous special advantages in improving soil quality and crop growth. First of all, biochar possesses a porous structure that can influence the soil's structure, porosity, particle size distribution, and density, which contributes to increasing the soil water-holding capacity and microbial activity [7]. Furthermore, biochar is alkaline and can improve the pH of soil [8]. Finally, biochar is rich in plenty of nutrients such as nitrogen, phosphorus, potassium, etc., exhibiting a positive effect on plant growth [9]. Song et al. [10] studied the influence of pyrolysis temperature and proportion of SSB on garlic yield and HMs accumulation and found that the SSB produced at 450°C and its addition at 25% could improve the yield of garlic well and inhibit HMs accumulation in garlic. Khan et al. [4] investigated the effects of SSB on rice yield, HMs bioaccumulation, and greenhouse gas emission and found that SSB amendments increased the pH, total nitrogen, organic carbon, and available nutrients of soil and crop yield, and decreased HMs bioavailability and N2O emission. In addition, there are a large amount of studies on the influence of SSB on plant growth and HMs migration that

**56**

**2. Materials and methods**

**2.2 Chinese cabbage pot experiment**

**2.1 Materials**

The pH was measured according to the agricultural trade standard of China (NY/T 1377-2007) and the solution was analyzed with a UB-7 pH meter (Ultra Basic, US). Electrical conductivity (EC) was measured according to the national environmental protection standard of China (HJ 802-2016) and the solution was analyzed with a Cond 3110 conductometer (Teltracon 325, Germany). Surface area was calculated by the Brunauer-Emmett-Teller (BET) method after testing using nitrogen adsorption/desorption isotherms with an apparatus (TriStar II 3020 V1.01, USA). Elemental analysis was conducted by an elemental analyzer (Vario MAX, Germany). The concentrations of nutrient elements were analyzed by digestion in an acid mixture [15] and the solution was determined by ICP-OES (Optima 7000DV, USA). The concentrations of available HMs in the sample were measured by the DTPA extraction method [20] and the solution was determined by ICP-MS (Agilent 7500cx, USA). The surface functional group of SSB was analyzed by FTIR spectrometry (iS10, Thermo, USA) and the morphology of SSB was analyzed by scanning electron microscopy (SEM, S-4800, Hitachi, Japan).

The dehydrogenase (DHA) activity in soil was measured by the triphenyltetrazolium chloride (TTC) spectrophotometric method [21]. The urease activity was measured by Nesslerization [22]. The molecular target genes of bacteria, fungi, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) were measured by quantitative real-time polymerase chain reaction (RT-PCR) analysis [23] and the information of primers is shown in **Table 1**. A standard curve was obtained by tenfold dilution of recombinant plasmid acquired in each molecular target gene of the above microorganisms and each sample was repeated three times. The SYBR® Premix Ex Taq™ kit from Bao Biological Engineering (Dalian, China) Co. Ltd. was used for analysis at Roche Lightcycler® 480 PCR. The quantitative PCR reaction system was 20 μL, including 1 μL of tenfold diluted DNA template, 10 μL of SYBR® Premix Ex Taq™, 0.2 μL (20 μM) of forward and reverse primers


respectively, and 8.6 μL of sterilized distilled water. The procedure of PCR consisted of denaturation at 95°C for 5 min, denaturation at 94°C for 30 s, annealing at 55°C for 45 min, and extension at 72°C for 1 min, followed by 40 cycles of denaturation, annealing, and extension at 72°C for 10 min.

### **3. Results and discussions**

#### **3.1 Basic properties of the original soil and SSB**

The physical and chemical properties of the original soil and SSB are listed in **Table 2**. SSB has higher pH, EC, and BET surface area compared with the soil, which shows that the addition of SSB can improve the physicochemical properties of soil, such as pH, salinity content, water retention, the adsorption of nutrient, and microbial population [24]. In particular, the change of pH in soil indicates the occurrence of some chemical and biological reactions. The contents of C, H, N, and S in biochar depend on the feedstock and pyrolysis condition. The H/C and C/N ratios represent the aromaticity of biochar and the capacity for organics to release inorganic N [10, 25]. In this study, the H/C ratio of SSB is lower (<0.1) than that of the soil, which suggests that SSB has higher aromaticity and can exist in the soil for many years [25]. However, the higher C/N ratio of SSB inhibits the release of inorganic N compared with the original soil. In addition, SSB contains higher concentrations of K, Na, P, and Ca compared with the soil, which indicates that the addition of SSB can increase the fertility of soil.

The FTIR spectra of SSB is shown in **Figure 1a**. The identified bands are assigned to the stretching vibrations of hydroxyl functionalities (3446 cm<sup>−</sup><sup>1</sup> ), amide bond stretching (1637 cm<sup>−</sup><sup>1</sup> ), bending vibration of methyl group (1385 cm<sup>−</sup><sup>1</sup> ), carbonoxygen single bond in phenol (1186 cm<sup>−</sup><sup>1</sup> ), and carbon-oxygen double bond (1050 cm<sup>−</sup><sup>1</sup> ) [10, 25, 26]. In addition, the stretching vibrations between 600 and 800 cm<sup>−</sup><sup>1</sup> can be related to the aromatic and heteroaromatic compounds, and the bands below 600 cm<sup>−</sup><sup>1</sup> can be attributed to the organic and inorganic halogen compounds [25]. The SEM micrograph of SSB is shown in **Figure 1b**. There are lots of lumps and holes


**59**

**Figure 1.**

*(a) FTIR spectra and (b) SEM micrograph of SSB.*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth…*

in the SSB, and the size of holes is very large. These results indicate that the SSB with abundant functional groups and pore structure can also change the physical and chemical properties of soil and provide a survival shelter for microorganism [27].

The effects of SSB addition on the pH and EC of soil are shown in **Figure 2**. The pH of the control soil increased remarkably after planting, which indicated that the acid organic matter in soil was decomposed during Chinese cabbage planting [28]. Also, the addition of SSB adjusted the pH of soil from acidic to neutral and the pH increased from 7.12 to 7.49 after planting. **Figure 2b** shows that the EC of the control soil increased slightly after cabbage planting, but it is just 382 μS/cm and close to the

**3.2 Effects of SSB addition on the physicochemical property of soil**

*DOI: http://dx.doi.org/10.5772/intechopen.82091*

#### **Table 2.**

*Physical and chemical properties of soil and SSB.*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth… DOI: http://dx.doi.org/10.5772/intechopen.82091*

**Figure 1.** *(a) FTIR spectra and (b) SEM micrograph of SSB.*

in the SSB, and the size of holes is very large. These results indicate that the SSB with abundant functional groups and pore structure can also change the physical and chemical properties of soil and provide a survival shelter for microorganism [27].

#### **3.2 Effects of SSB addition on the physicochemical property of soil**

The effects of SSB addition on the pH and EC of soil are shown in **Figure 2**. The pH of the control soil increased remarkably after planting, which indicated that the acid organic matter in soil was decomposed during Chinese cabbage planting [28]. Also, the addition of SSB adjusted the pH of soil from acidic to neutral and the pH increased from 7.12 to 7.49 after planting. **Figure 2b** shows that the EC of the control soil increased slightly after cabbage planting, but it is just 382 μS/cm and close to the

*Biochar - An Imperative Amendment for Soil and the Environment*

annealing, and extension at 72°C for 10 min.

**3.1 Basic properties of the original soil and SSB**

addition of SSB can increase the fertility of soil.

oxygen single bond in phenol (1186 cm<sup>−</sup><sup>1</sup>

stretching (1637 cm<sup>−</sup><sup>1</sup>

BET surface area (m2

600 cm<sup>−</sup><sup>1</sup>

to the stretching vibrations of hydroxyl functionalities (3446 cm<sup>−</sup><sup>1</sup>

[10, 25, 26]. In addition, the stretching vibrations between 600 and 800 cm<sup>−</sup><sup>1</sup>

**Parameters Soil SSB** pH 5.32 ± 0.03 10.00 ± 0.04 EC (μS/cm) 203.67 ± 2.22 871.33 ± 3.78 Moisture (%) 0.26 ± 0.00 NDa

Carbon (%) 3.08 ± 0.02 7.84 ± 0.02 Hydrogen (%) 1.04 ± 0.03 0.63 ± 0.03 Nitrogen (%) 0.26 ± 0.00 0.34 ± 0.00 Sulfur (%) 3.96 ± 0.04 3.82 ± 0.08 K (mg/g) 8.37 ± 0.05 20.33 ± 0.06 Na (mg/g) 0.86 ± 0.01 10.57 ± 0.05 P (mg/g) 1.51 ± 0.02 7.28 ± 0.05 Ca (mg/g) 0.03 ± 0.00 39.66 ± 0.11

be related to the aromatic and heteroaromatic compounds, and the bands below

**3. Results and discussions**

respectively, and 8.6 μL of sterilized distilled water. The procedure of PCR consisted of denaturation at 95°C for 5 min, denaturation at 94°C for 30 s, annealing at 55°C for 45 min, and extension at 72°C for 1 min, followed by 40 cycles of denaturation,

The physical and chemical properties of the original soil and SSB are listed in **Table 2**. SSB has higher pH, EC, and BET surface area compared with the soil, which shows that the addition of SSB can improve the physicochemical properties of soil, such as pH, salinity content, water retention, the adsorption of nutrient, and microbial population [24]. In particular, the change of pH in soil indicates the occurrence of some chemical and biological reactions. The contents of C, H, N, and S in biochar depend on the feedstock and pyrolysis condition. The H/C and C/N ratios represent the aromaticity of biochar and the capacity for organics to release inorganic N [10, 25]. In this study, the H/C ratio of SSB is lower (<0.1) than that of the soil, which suggests that SSB has higher aromaticity and can exist in the soil for many years [25]. However, the higher C/N ratio of SSB inhibits the release of inorganic N compared with the original soil. In addition, SSB contains higher concentrations of K, Na, P, and Ca compared with the soil, which indicates that the

The FTIR spectra of SSB is shown in **Figure 1a**. The identified bands are assigned

), bending vibration of methyl group (1385 cm<sup>−</sup><sup>1</sup>

 can be attributed to the organic and inorganic halogen compounds [25]. The SEM micrograph of SSB is shown in **Figure 1b**. There are lots of lumps and holes

/g) 0.51 13.05

), amide bond

), and carbon-oxygen double bond (1050 cm<sup>−</sup><sup>1</sup>

), carbon-

can

)

**58**

*a*

**Table 2.**

*ND, not detected.*

*Physical and chemical properties of soil and SSB.*

**Figure 2.** *Effects of SSB addition on the pH (a) and EC (b) of soil.*

EC of the soil added with 10% SSB before planting. The EC of the soil with 10% SSB addition increased from 364 to 644 μS/cm after planting and the increase rate was 76.92%. When EC is lower than 500 μS/cm or higher than 2000 μS/cm, the phenomenon of lacking nutrient or seedling burning will occur during planting [29]. Therefore, adding SSB in soil could adjust the EC to a suitable range (500–2000 μS/cm) for plant growth. The above results are because a number of alkaline ions such as hydrocarbon anion, bicarbonate, carbonate, and phosphate in SSB were released during planting and increased the pH and EC of soil effectively [30, 31].

#### **3.3 Effects of adding SSB on the microbiological property of soil**

#### *3.3.1 Effects of adding SSB on the DHA and urease in soil*

DHA plays a key role in the decomposition process of organic matter and can be used as an indicator for the evaluation of total cell oxidation activity [32]. Therefore,

**61**

**Figure 3.**

*Effects of SSB addition on the concentrations of DHA (a) and urease (b) in soil.*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth…*

DHA activity is used to characterize the intensity of microbial activity. Urease can convert urea into ammonia and carbon dioxide or ammonium carbonate, and it reflects the intensity of nitrogen relevant reactions in the soil system [33]. The effects of SSB addition on the concentrations of DHA and urease in soil are shown in **Figure 3**. The addition of SSB increased the concentrations of DHA and urease in soil before planting, which rose from 3.83 μg IPTF/(g h) and 16.53 μg NH3-N/(g h) to 14.33 μg IPTF/(g h) and 32.00 μg NH3-N/(g h), respectively. Whether SSB is added or not, the concentrations of DHA and urease in soil increased after planting, and the concentrations of the DHA and urease in the soil added with 10% SSB reached 3.60 and 1.67 times as high as those of the control soil. These results implied that adding SSB could improve the activities of DHA and urease in soil, promote anaerobic microbial growth and synthesis of enzymes, and enhance microbial activity. This is because SSB influenced enzyme activity with the changes of physiochemical properties

*DOI: http://dx.doi.org/10.5772/intechopen.82091*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth… DOI: http://dx.doi.org/10.5772/intechopen.82091*

DHA activity is used to characterize the intensity of microbial activity. Urease can convert urea into ammonia and carbon dioxide or ammonium carbonate, and it reflects the intensity of nitrogen relevant reactions in the soil system [33]. The effects of SSB addition on the concentrations of DHA and urease in soil are shown in **Figure 3**. The addition of SSB increased the concentrations of DHA and urease in soil before planting, which rose from 3.83 μg IPTF/(g h) and 16.53 μg NH3-N/(g h) to 14.33 μg IPTF/(g h) and 32.00 μg NH3-N/(g h), respectively. Whether SSB is added or not, the concentrations of DHA and urease in soil increased after planting, and the concentrations of the DHA and urease in the soil added with 10% SSB reached 3.60 and 1.67 times as high as those of the control soil. These results implied that adding SSB could improve the activities of DHA and urease in soil, promote anaerobic microbial growth and synthesis of enzymes, and enhance microbial activity. This is because SSB influenced enzyme activity with the changes of physiochemical properties

**Figure 3.** *Effects of SSB addition on the concentrations of DHA (a) and urease (b) in soil.*

*Biochar - An Imperative Amendment for Soil and the Environment*

EC of the soil added with 10% SSB before planting. The EC of the soil with 10% SSB addition increased from 364 to 644 μS/cm after planting and the increase rate was 76.92%. When EC is lower than 500 μS/cm or higher than 2000 μS/cm, the phenomenon of lacking nutrient or seedling burning will occur during planting [29]. Therefore,

DHA plays a key role in the decomposition process of organic matter and can be used as an indicator for the evaluation of total cell oxidation activity [32]. Therefore,

adding SSB in soil could adjust the EC to a suitable range (500–2000 μS/cm) for plant growth. The above results are because a number of alkaline ions such as hydrocarbon anion, bicarbonate, carbonate, and phosphate in SSB were released

during planting and increased the pH and EC of soil effectively [30, 31].

**3.3 Effects of adding SSB on the microbiological property of soil**

*3.3.1 Effects of adding SSB on the DHA and urease in soil*

*Effects of SSB addition on the pH (a) and EC (b) of soil.*

**60**

**Figure 2.**

(especially pH) in soil, and the adsorption of enzymes and soil organic matter on SSB also changed the kinetic properties of enzyme activity [17].

#### *3.3.2 Effects of SSB addition on bacteria and fungi in soil*

In the planting process, bacteria play an important role in the transformation of organic and inorganic matter in soil, while fungi have significant effects on the carbon and energy cycle in soil [18]. The bacteria and fungi counts are important indicators of microbial activity intensity, and effectively reflect whether the environment of soil is suitable for crop growth or not. The effects of SSB addition on the concentrations of bacteria and fungi in soil are shown in **Figure 4**. The addition of SSB increased the concentrations of bacteria and fungi in soil before planting, which rose from 2.43 × 106 and 0.77 × 106 CFU/g to 20.60 × 106 and 3.67 × 106 CFU/g, respectively. Whether SSB is added or not, the concentrations of both bacteria and fungi in soil increased after planting, and the bacteria and fungi

**63**

**Figure 5.**

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth…*

concentrations in soil added with 10% SSB reached 2.84 and 2.62 times as high as those of the control soil, respectively. These results showed that the addition of SSB had beneficial modulation effects on the concentrations of bacteria and fungi during planting, and it could effectively enhance the microbial property of soil.

AOA and AOB associated with the nitrification of soil are called the nitrifying bacteria. The higher concentrations of AOA and AOB can improve the conversion of other forms of nitrogen into available nitrogen fertilizer so as to enhance the fertility of soil and promote plant growth [34]. The effects of SSB addition on the concentrations of the AOA and AOB in soil are displayed in **Figure 5**. The addition of SSB increased the concentrations of AOA and AOB in soil before planting,

amoA copies/g to 8.63 × 106

and 6.07 × 106

*DOI: http://dx.doi.org/10.5772/intechopen.82091*

which rose from 4.83 × 106

*3.3.3 Effects of adding SSB on the AOA and AOB in soil*

and 2.47 × 106

*Effects of SSB addition on the concentrations of AOA (a) and AOB (b) in soil.*

amoA copies/g, respectively. Whether SSB is added or not, the concentrations of both AOA and AOB in soil increased after planting, and the AOA and AOB

**Figure 4.** *Effects of SSB addition on the concentrations of bacteria (a) and fungi (b) in soil.*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth… DOI: http://dx.doi.org/10.5772/intechopen.82091*

concentrations in soil added with 10% SSB reached 2.84 and 2.62 times as high as those of the control soil, respectively. These results showed that the addition of SSB had beneficial modulation effects on the concentrations of bacteria and fungi during planting, and it could effectively enhance the microbial property of soil.

#### *3.3.3 Effects of adding SSB on the AOA and AOB in soil*

*Biochar - An Imperative Amendment for Soil and the Environment*

*3.3.2 Effects of SSB addition on bacteria and fungi in soil*

planting, which rose from 2.43 × 106

3.67 × 106

SSB also changed the kinetic properties of enzyme activity [17].

(especially pH) in soil, and the adsorption of enzymes and soil organic matter on

In the planting process, bacteria play an important role in the transformation of organic and inorganic matter in soil, while fungi have significant effects on the carbon and energy cycle in soil [18]. The bacteria and fungi counts are important indicators of microbial activity intensity, and effectively reflect whether the environment of soil is suitable for crop growth or not. The effects of SSB addition on the concentrations of bacteria and fungi in soil are shown in **Figure 4**. The addition of SSB increased the concentrations of bacteria and fungi in soil before

and 0.77 × 106

both bacteria and fungi in soil increased after planting, and the bacteria and fungi

CFU/g, respectively. Whether SSB is added or not, the concentrations of

CFU/g to 20.60 × 106

and

**62**

**Figure 4.**

*Effects of SSB addition on the concentrations of bacteria (a) and fungi (b) in soil.*

AOA and AOB associated with the nitrification of soil are called the nitrifying bacteria. The higher concentrations of AOA and AOB can improve the conversion of other forms of nitrogen into available nitrogen fertilizer so as to enhance the fertility of soil and promote plant growth [34]. The effects of SSB addition on the concentrations of the AOA and AOB in soil are displayed in **Figure 5**. The addition of SSB increased the concentrations of AOA and AOB in soil before planting, which rose from 4.83 × 106 and 2.47 × 106 amoA copies/g to 8.63 × 106 and 6.07 × 106 amoA copies/g, respectively. Whether SSB is added or not, the concentrations of both AOA and AOB in soil increased after planting, and the AOA and AOB

**Figure 5.** *Effects of SSB addition on the concentrations of AOA (a) and AOB (b) in soil.*

concentrations in soil on adding 10% SSB reached 1.76 and 2.23 times as high as those of the control soil, respectively. These results show that SSB addition could effectively increase the concentrations of microorganisms associated with soil nitrification before and after planting.

To sum up, the influence of SSB on the microbiological property are as follows: on the one hand, SSB stored and supplied a large amount of nutrients by the bonding of nutrient cations and inorganic anions in soil with its surface functional groups; on the other hand, SSB changed the physiochemical property of soil and reduced the toxicity of contaminants to soil microorganisms [17].

#### **3.4 Effects of adding SSB on Chinese cabbage growth**

The weights of the aboveground and underground parts of Chinese cabbage are considered as important indicators that directly reflect the influence of the physical, chemical, and microbial properties of soil on plant growth. **Figure 6** shows the effects of adding SSB on the weight of Chinese cabbage. The weights of the aboveground and underground parts of Chinese cabbage increased with 10% SSB added to soil. The weight of edible aboveground part was 5.82 times and that of the underground part was 8.67 times as much as those from the control soil. These results can be explained by the fact that the addition of SSB brought the pH and EC of the original soil to suitable ranges for plant growth, and that the increases of the DHA activity, urease activity, bacteria concentration, and fungi concentration provided appropriate metabolic environment for soil microorganisms. This favorable metabolic environment further improved the microbial characteristics and forms a virtuous cycle [17]. In addition, SSB contains nutritive elements like K, P, and N at high concentrations, which increased the fertility of barren soil [9]. Therefore, the weights of Chinese cabbage increased significantly after SSB addition. This also showed that SSB had a positive effect on the growth of crop in barren soil.

#### **3.5 Effects of SSB addition on HMs availability in Chinese cabbage and soil**

**Figure 7** shows the concentrations of HMs in the aboveground and underground parts of Chinese cabbage, respectively. For the aboveground part, the addition of SSB to soil significantly decreased the concentrations of Mn and Cd, and reduced the toxicity of Chinese cabbage in the edible part compared with the control group. For the underground part, the addition of SSB significantly decreased the

**65**

**Figure 7.**

*Chinese cabbage planted.*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth…*

concentrations of Mn, Pb, and Cd compared with the control group, which implied that the addition of SSB in soil inhibited the migration of HMs from soil to the

*Effects of adding SSB on the concentrations of HMs in aboveground part (a) and underground part (b) of* 

It is widely accepted that the HMs in plant are entirely from the migration of the available HMs in the mixed soil during planting [4, 35]. Therefore, the concentrations of available HMs in soil before and after planting were measured to investigate the influence of SSB addition on the transfer of HMs, as shown in **Table 3**. The change rate of available HM concentration in soil after planting compared with that

*c*s2 − *c*s1

where, α is the change rate of available HM concentration in soil after planting compared with that before planting, %; *c*s2 is the concentration of available HM in

*<sup>c</sup>*s1 × 100 (1)

underground part of Chinese cabbage.

α = \_\_\_\_\_

before planting was defined as:

*DOI: http://dx.doi.org/10.5772/intechopen.82091*

**Figure 6.** *Effects of adding SSB on the weight of Chinese cabbage planted.*

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth… DOI: http://dx.doi.org/10.5772/intechopen.82091*

**Figure 7.**

*Biochar - An Imperative Amendment for Soil and the Environment*

nitrification before and after planting.

concentrations in soil on adding 10% SSB reached 1.76 and 2.23 times as high as those of the control soil, respectively. These results show that SSB addition could effectively increase the concentrations of microorganisms associated with soil

To sum up, the influence of SSB on the microbiological property are as follows: on the one hand, SSB stored and supplied a large amount of nutrients by the bonding of nutrient cations and inorganic anions in soil with its surface functional groups; on the other hand, SSB changed the physiochemical property of soil and

The weights of the aboveground and underground parts of Chinese cabbage are considered as important indicators that directly reflect the influence of the physical, chemical, and microbial properties of soil on plant growth. **Figure 6** shows the effects of adding SSB on the weight of Chinese cabbage. The weights of the aboveground and underground parts of Chinese cabbage increased with 10% SSB added to soil. The weight of edible aboveground part was 5.82 times and that of the underground part was 8.67 times as much as those from the control soil. These results can be explained by the fact that the addition of SSB brought the pH and EC of the original soil to suitable ranges for plant growth, and that the increases of the DHA activity, urease activity, bacteria concentration, and fungi concentration provided appropriate metabolic environment for soil microorganisms. This favorable metabolic environment further improved the microbial characteristics and forms a virtuous cycle [17]. In addition, SSB contains nutritive elements like K, P, and N at high concentrations, which increased the fertility of barren soil [9]. Therefore, the weights of Chinese cabbage increased significantly after SSB addition. This also

reduced the toxicity of contaminants to soil microorganisms [17].

showed that SSB had a positive effect on the growth of crop in barren soil.

**3.5 Effects of SSB addition on HMs availability in Chinese cabbage and soil**

**Figure 7** shows the concentrations of HMs in the aboveground and underground parts of Chinese cabbage, respectively. For the aboveground part, the addition of SSB to soil significantly decreased the concentrations of Mn and Cd, and reduced the toxicity of Chinese cabbage in the edible part compared with the control group. For the underground part, the addition of SSB significantly decreased the

**3.4 Effects of adding SSB on Chinese cabbage growth**

**64**

**Figure 6.**

*Effects of adding SSB on the weight of Chinese cabbage planted.*

*Effects of adding SSB on the concentrations of HMs in aboveground part (a) and underground part (b) of Chinese cabbage planted.*

concentrations of Mn, Pb, and Cd compared with the control group, which implied that the addition of SSB in soil inhibited the migration of HMs from soil to the underground part of Chinese cabbage.

It is widely accepted that the HMs in plant are entirely from the migration of the available HMs in the mixed soil during planting [4, 35]. Therefore, the concentrations of available HMs in soil before and after planting were measured to investigate the influence of SSB addition on the transfer of HMs, as shown in **Table 3**. The change rate of available HM concentration in soil after planting compared with that before planting was defined as:

$$\mathbf{u} = \frac{c\_{s2} - c\_{s1}}{c\_{s1}} \times \mathbf{100} \tag{1}$$

where, α is the change rate of available HM concentration in soil after planting compared with that before planting, %; *c*s2 is the concentration of available HM in


#### **Table 3.**

*Concentrations and change rates of available HMs in soil before and after planting.*

the soil after planting, μg/g; and *c*s1 is the concentration of available HM in the soil before planting, μg/g.

The addition of SSB decreased the concentrations of available Cr, Mn, Ni, Cd, and Pb in soil before planting, which is mostly because the fractions of HMs in SSB are more stable than those in soil. After planting, the concentrations of available Cr, Mn, and Pb in control soil decreased by 0.49, 2.86, and 2.78%, respectively, which indicated that these HMs were taken up by cabbages or migrated to more stable fractions during planting. Compared with the control soil, the addition of SSB reduced the transfer of the available HMs in soil during planting and the α value of Cr, Mn, Ni, Cd, and Pb decreased from −0.49, −2.86, 4.35, 14.14, and −2.78 to −1.76, −8.82, −0.28, 2.81, and −7.41%, respectively.

In order to investigate the effects of SSB addition on the migration of the available HMs in soil, the conversion rate of the content of available HM was defined as: s1 <sup>∙</sup> *<sup>m</sup>*s1 <sup>×</sup> <sup>100</sup> (2)

$$\mathbf{u} = \frac{\mathbf{c}\_{s2} \cdot \mathbf{m}\_{s2} + \mathbf{c}\_{\rm ca} \cdot \mathbf{m}\_{\rm ca} + \mathbf{c}\_{\rm cb} \cdot \mathbf{m}\_{\rm cb} - \mathbf{c}\_{\rm s1} \cdot \mathbf{m}\_{\rm c1}}{\mathbf{c}\_{\rm s1} \cdot \mathbf{m}\_{\rm s1}} \times \mathbf{100} \tag{2}$$

**67**

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth…*

immobilization effect was closely related to the biochar properties and its effects on the microbial environment in soil. The surface of SSB has numerous rich alkaline groups such as alkyl negative ion, bicarbonate, carbonate, and phosphate [31], and its application in soil increased the pH, which led to the immobilization of the available HMs in soil [37, 38]. And, the interactions of SSB with the available HMs promoted the more stable transformation of HMs, and included the ion exchange between metal in soil and exchangeable metal in SSB, electrostatic attraction of anionic metal, electrostatic attraction of cation metal, and precipitation of metal [39]. Also, SSB has a good porous structure and can improve the microbial activity, which enhanced the transformation of microorganism on HMs [17]. Therefore, the

Control −0.46 66.65 4.35 14.40 −0.97 10% SSB −1.62 302.60 −0.26 3.50 8.42

**Cr Mn Ni Cd Pb**

addition of SSB could improve the immobilization of available HMs in soil.

up, SSB has positive effects on the planting in barren soil.

SSB has better pH and EC, more developed pore structure, and higher concentrations of nutrient elements compared with the original soil. The addition of SSB could adjust the pH of mine soil from acidic to neutral and increase the EC of soil. Also, the addition of SSB increased the concentrations of enzyme and microorganisms. Therefore, the changes of the physiochemical property and microbial environment improved the growth of Chinese cabbage. The edible aboveground and the underground parts of cabbage in SSB-amended soil weighed 5.82 times and 8.67 times as much as those from the control group. Moreover, the addition of SSB promoted the migration of Cr, Ni, and Cd from the available state to the more stable state due to the special properties of SSB and changes of soil environment. To sum

The authors would like to thank Xiang Zhang for his valuable help. This work

Projects of Fujian Province (2015H0044), the China-Japanese Research Cooperative Program (2016YFE0118000), the Scientific and Technological Major Special Project of Tianjin City (16YFXTSF00420), and the Key Project of Young Talent of IUE,

was supported by financial support received from the Industry Leading Key

*DOI: http://dx.doi.org/10.5772/intechopen.82091*

*Conversion rates of the content of available HMs.*

**Condition** η **(%)**

**4. Conclusions**

**Table 4.**

**Acknowledgements**

CAS (IUEZD201402).

where η is the conversion rate of the content of available HM, %; *c*ca and *c*cb are the concentration of available HM in the aboveground and underground parts of Chinese cabbage after planting, respectively, μg/g; *m*s1 and *m*s2 are the mass of soil before and after planting, respectively, g; and *m*ca and *m*cb are the mass of the aboveground and underground parts of Chinese cabbage, respectively, g. When η > 0, the HM in soil transforms from the stable state to the available state after planting; and when η < 0, the HM in soil transforms from the available state to the stable state after planting. The conversion rates of the available HMs are shown in **Table 4**. The planting of Chinese cabbage in control soil promoted the immobilization of Cr and Pb and inhibited the immobilization of Mn, Ni, and Cd. Moreover, the addition of SSB increased the conversion rate of Mn compared with the control soil, which indicated that SSB addition could improve the migration of Mn to the available state. Mn plays an important role in the process of photosynthesis, respiration, protein synthesis, and hormone activation [36], which explains partly the effects of SSB addition on the weights of the aboveground and underground parts of Chinese cabbage. In addition, the conversion rates of Cr, Ni, and Cd after adding SSB decreased from −0.46, 4.35, and 14.40 to −1.62, −0.26, and 3.50% compared with the control soil, which indicated that the addition of SSB could promote the migration of Ni, Cd, and Cr from the available state to the stable state. In general, this


*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth… DOI: http://dx.doi.org/10.5772/intechopen.82091*

**Table 4.**

*Biochar - An Imperative Amendment for Soil and the Environment*

−1.76, −8.82, −0.28, 2.81, and −7.41%, respectively.

<sup>η</sup> <sup>=</sup> *<sup>c</sup>*s2 <sup>∙</sup> *<sup>m</sup>*s2 <sup>+</sup> *<sup>c</sup>*ca <sup>∙</sup> *<sup>m</sup>*ca <sup>+</sup> *<sup>c</sup>*cb <sup>∙</sup> *<sup>m</sup>*cb <sup>−</sup> *<sup>c</sup>*s1 \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ *<sup>c</sup>*

*Concentrations and change rates of available HMs in soil before and after planting.*

before planting, μg/g.

**Table 3.**

the soil after planting, μg/g; and *c*s1 is the concentration of available HM in the soil

The addition of SSB decreased the concentrations of available Cr, Mn, Ni, Cd, and Pb in soil before planting, which is mostly because the fractions of HMs in SSB are more stable than those in soil. After planting, the concentrations of available Cr, Mn, and Pb in control soil decreased by 0.49, 2.86, and 2.78%, respectively, which indicated that these HMs were taken up by cabbages or migrated to more stable fractions during planting. Compared with the control soil, the addition of SSB reduced the transfer of the available HMs in soil during planting and the α value of Cr, Mn, Ni, Cd, and Pb decreased from −0.49, −2.86, 4.35, 14.14, and −2.78 to

**HM Condition Before planting (μg/g) After planting (μg/g)** α **(%)** Cr Control 8.24 ± 0.01 8.20 ± 0.38 −0.49

Mn Control 0.35 ± 0.02 0.34 ± 0.02 −2.86

Ni Control 7.59 ± 0.02 7.92 ± 0.03 +4.35

Cd Control 4.88 ± 0.11 5.57 ± 0.22 +14.14

Pb Control 0.36 ± 0.05 0.35 ± 0.06 −2.78

10% SSB 6.80 ± 0.06 6.68 ± 0.29 −1.76

10% SSB 0.34 ± 0.00 0.31 ± 0.01 −8.82

10% SSB 7.10 ± 0.09 7.08 ± 0.68 −0.28

10% SSB 4.62 ± 0.47 4.75 ± 0.15 +2.81

10% SSB 0.27 ± 0.03 0.25 ± 0.02 −7.41

In order to investigate the effects of SSB addition on the migration of the available HMs in soil, the conversion rate of the content of available HM was defined as:

where η is the conversion rate of the content of available HM, %; *c*ca and *c*cb are the concentration of available HM in the aboveground and underground parts of Chinese cabbage after planting, respectively, μg/g; *m*s1 and *m*s2 are the mass of soil before and after planting, respectively, g; and *m*ca and *m*cb are the mass of the aboveground and underground parts of Chinese cabbage, respectively, g. When η > 0, the HM in soil transforms from the stable state to the available state after planting; and when η < 0, the HM in soil transforms from the available state to the stable state after planting. The conversion rates of the available HMs are shown in **Table 4**. The planting of Chinese cabbage in control soil promoted the immobilization of Cr and Pb and inhibited the immobilization of Mn, Ni, and Cd. Moreover, the addition of SSB increased the conversion rate of Mn compared with the control soil, which indicated that SSB addition could improve the migration of Mn to the available state. Mn plays an important role in the process of photosynthesis, respiration, protein synthesis, and hormone activation [36], which explains partly the effects of SSB addition on the weights of the aboveground and underground parts of Chinese cabbage. In addition, the conversion rates of Cr, Ni, and Cd after adding SSB decreased from −0.46, 4.35, and 14.40 to −1.62, −0.26, and 3.50% compared with the control soil, which indicated that the addition of SSB could promote the migration of Ni, Cd, and Cr from the available state to the stable state. In general, this

∙ *m*s1

s1 <sup>∙</sup> *<sup>m</sup>*s1 <sup>×</sup> <sup>100</sup> (2)

**66**

*Conversion rates of the content of available HMs.*

immobilization effect was closely related to the biochar properties and its effects on the microbial environment in soil. The surface of SSB has numerous rich alkaline groups such as alkyl negative ion, bicarbonate, carbonate, and phosphate [31], and its application in soil increased the pH, which led to the immobilization of the available HMs in soil [37, 38]. And, the interactions of SSB with the available HMs promoted the more stable transformation of HMs, and included the ion exchange between metal in soil and exchangeable metal in SSB, electrostatic attraction of anionic metal, electrostatic attraction of cation metal, and precipitation of metal [39]. Also, SSB has a good porous structure and can improve the microbial activity, which enhanced the transformation of microorganism on HMs [17]. Therefore, the addition of SSB could improve the immobilization of available HMs in soil.

### **4. Conclusions**

SSB has better pH and EC, more developed pore structure, and higher concentrations of nutrient elements compared with the original soil. The addition of SSB could adjust the pH of mine soil from acidic to neutral and increase the EC of soil. Also, the addition of SSB increased the concentrations of enzyme and microorganisms. Therefore, the changes of the physiochemical property and microbial environment improved the growth of Chinese cabbage. The edible aboveground and the underground parts of cabbage in SSB-amended soil weighed 5.82 times and 8.67 times as much as those from the control group. Moreover, the addition of SSB promoted the migration of Cr, Ni, and Cd from the available state to the more stable state due to the special properties of SSB and changes of soil environment. To sum up, SSB has positive effects on the planting in barren soil.

#### **Acknowledgements**

The authors would like to thank Xiang Zhang for his valuable help. This work was supported by financial support received from the Industry Leading Key Projects of Fujian Province (2015H0044), the China-Japanese Research Cooperative Program (2016YFE0118000), the Scientific and Technological Major Special Project of Tianjin City (16YFXTSF00420), and the Key Project of Young Talent of IUE, CAS (IUEZD201402).

### **Author details**

Guangwei Yu1 \*, Shengyu Xie1,2, Jianli Ma3 , Xiaofu Shang4 , Yin Wang1 , Cheng Yu5 , Futian You1 , Xiaoda Tang1 , Héctor U. Levatti6 , Lanjia Pan1,2, Jie Li1,2 and Chunxing Li1

1 CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China

2 University of Chinese Academy of Sciences, Beijing, China

3 Tianjin Academy of Environmental Sciences, Tianjin, China

4 Tianjin Huankelijia Environment RemediationTechnology Co., Ltd., Tianjin, China


\*Address all correspondence to: gwyu@iue.ac.cn

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**69**

*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth…*

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savanna oxisol. Plant and Soil. 2010;**333**(1-2):117-128. DOI: 10.1007/

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chemosphere.2012.05.092

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[14] Li J, Pan L, Yu G, et al. Preparation of adsorption ceramsite derived from sludge biochar. Environmental Science. 2017;**38**(9):3970-3978. DOI: 10.13227/j.

[11] Zhang X, Wang H, He L, et al. Using biochar for remediation of soils contaminated with heavy metals and organic pollutants. Environmental Science and Pollution Research. 2013;**20**(12):8472-8483. DOI: 10.1007/

[12] Méndez A, Gómez A, Paz-Ferreiro J, et al. Effects of sewage sludge biochar on plant metal availability after application to a Mediterranean soil. Chemosphere. 2012;**89**(11):1354-1359. DOI: 10.1016/j.

s11104-010-0327-0

*DOI: http://dx.doi.org/10.5772/intechopen.82091*

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*Influence of Sewage Sludge Biochar on the Microbial Environment, Chinese Cabbage Growth… DOI: http://dx.doi.org/10.5772/intechopen.82091*

#### **References**

*Biochar - An Imperative Amendment for Soil and the Environment*

\*, Shengyu Xie1,2, Jianli Ma3

, Xiaoda Tang1

Environment, Chinese Academy of Sciences, Xiamen, China

2 University of Chinese Academy of Sciences, Beijing, China

3 Tianjin Academy of Environmental Sciences, Tianjin, China

6 College of Engineering, Swansea University, Swansea, China

5 Fujian Academy of Building Research, Fuzhou, China

\*Address all correspondence to: gwyu@iue.ac.cn

1 CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

4 Tianjin Huankelijia Environment RemediationTechnology Co., Ltd., Tianjin, China

, Xiaofu Shang4

, Héctor U. Levatti6

, Yin Wang1

,

, Lanjia Pan1,2, Jie Li1,2

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**Author details**

and Chunxing Li1

, Futian You1

Guangwei Yu1

Cheng Yu5

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Section 2

Bioremediation with

Biochar

Section 2
