**Abstract**

Over the years, the carbon-rich biochar has been used for the purpose of environmental conservation and reservation. Typically produced from varieties of materials ranging from sewage, farm produce, energy crops and agricultural waste or residues, the properties usually considered in the application of biochar include the chemical composition, porosity and stability. Contemporarily, the use of biochar has extended to its utilization in the industry, agriculture, forestry, and the natural environment. Soil fertility depends on the holistic process of managing the soil and likewise maintaining a robust biodiversity. This process involves the application of natural carbon-rich materials like biochar as soil amendments. The rapid absorption tendency of biochar, both on organic and inorganic materials has contributed immensely to the removal of excess antimicrobials from the environment. Biochar has been known to be a good enhancer of the soil due to its rich content of carbon and other nutrients good enough for the soil. Other striking effects of biochar on the soil and environment include the enhancement of the uptake of nitrogen, improvement of the soil structure, mitigation of greenhouse gases, conservation of the environment and enhancement of soil microbial community.

**Keywords:** biochar, soil fertility, soil enhancement, soil properties, wastes, soil carbon

### **1. Introduction**

Biochar is a carbon-rich stable solid biomass in form of humus which is produced either from sustainable waste particles buried in the soil or through pyrolysis of plant or animal biomass under different temperature conditions. The nature and efficiency of the plant biomass used in biochar production depend on the type and the characteristics of the soil from which the plant biomass was developed [1]. The stability of organic matter in soils is determined by its ability to resist microbial and/or chemical decomposition, through chemical transformations and physical interactions with soil minerals. The sequestration of carbon and carbon dioxide reduction are being gradually achieved in recent years through the use of biochar. Biochar also help in the reduction of wastes and removal of the same from the environment. It actually comprise of organic carbon with low expectancy of degradation [1, 2].

Biochar has been in hunt for so many decades till now. Over the years, it has been used for the purpose of environmental conservation and reservation. Today, the use of biochar has extended to its utilization in the industry, agriculture, forestry, and

the natural environment. It has also been used for the purpose of heavy metal digestion, pollutant immobilization as well as a supplement to composting and methane fermentation process [1, 3]. Recently, biochar is being used in pyrolytic filtering of tar and also in the production of hydrogen [3].

The presence of organic matter and nutrients in biochar is vital because the nutrients provide basic mineral supplements for the soil. Therefore, the amendment of soil with biochar increases the soil's pH, cation-exchange capacity (CEC), total nitrogen, organic carbon and conductivity. It has been reported that the fate and toxicity of heavy metals have been reasonably reduced due to the amendment of soil with biochar [4]. Furthermore, the porosity, large surface area and absorbance potential have made biochar a medium for soil nutrient improvement. Likewise, biochar also acts as a suitable habitat for soil microorganisms to thrive, alongside the support by roots of leguminous plants that aid the symbiotic relationships between the microorganisms and the plants [5].

Biochar has also been known to decrease the tensile strength of the soil because of its porosity and ability to create air pores within the soil, thus reducing soil compaction. With this development, biochar can be used as a sustainable tool for agricultural soil development. High crop yields can be produced with the use of biochar without necessarily depleting essential nutrients from the environment [6].

### **2. Biochar properties that enhance environmental safety**

Biochar can be produced from varieties of materials ranging from sewage, farm produce, energy crops and agricultural waste or residues. Other materials used for biochar include forest wastes like conifer barks, sawdust pellets, paper and moss. After biochar is produced, the quality of the biochar is determined by the assessment of certain properties possessed by the biochar product [7, 8].

The properties usually considered at the post-production stage of biochar include the chemical composition, porosity and stability. However, at the point of production, the chemical composition can be manipulated by the type of substrate used in the biochar preparation and the composition of the substrate determines the chemical composition of the biochar itself [3, 9].

Typically, biochars contain stable organic compounds where the carbon content may be within the range of 50 to 90% and volatile content at 10 to 50% [2, 10]. Biochar seldom undergo microbial degradation because of their carbonized nature and their pH. Some of the properties of biochar are shown in **Table 1**. These properties determine the level of biochar quality. The temperatures of the pyrolytic processes at the point of production of the biochar are also indicated.

The pH is either neutral or alkaline. The alkaline pH sometimes results from the biomass pyrolysis of high temperature. The increase in the temperature of the soil containing the biomass has a resultant effect on the alkalinity of the biomass [10]. However, at lower temperatures, high ion-exchange biochars are produced. The cation exchange capacity which determines nutrient absorption indicates a rise in temperature at every rise in the cation exchange capacity of the soil biomass [11]. It is as a result of these physicochemical properties that make biochars qualify as good soil carbon sequesters and soil remediation agents [3, 12]. Furthermore, soil types that are supplemented with biochar have a very high degree of absorption.

Biochar has a predominantly condensed aromatic structure that is known to be highly resistant to microbial decomposition. The porosity of the biochar adds to the water retention capacity of the soil and increases the soils ability to form aggregates [13]. **Figure 1** describes the porous nature of a typical biochar.

**145**

**Feedstock for biochar production**

Acacia bark Coconut bark

Corn

Corn

Green waste Peanut shells

Pecan shells Pecan shells

Rice slaw

Sewage sludge

Sugarcane bagasse

Eucalyptus wood

Oak wood

Oak wood

*Source: Saletnik et al. [1].*

*exchange capacity) of the suitable biomass was determined.*

**Table 1.** *Selected properties of biochar and the respective temperatures of pyrolytic processes.*

7.0 —

—

884

1.2

737

759

1.0

759

—

—

*NB: The biomass with suitable pH for biochar was highlighted. Other biomasses are more acidic, thus less suitable. Most emphasis was based on suitable pH and pyrolysis temperature while the CEC (cation* 

2.2

—

120

824

5.7

144

—

710

17.7

40

—

0.6

—

1.1

—

400

0.23

286

—

4.34

—

—

—

6.2 —

7.6 —

—

—

470

64

7

490

13.2

37

880

4.0

220

834

3.4

245

—

—

—

56

—

35

—

—

9.54

—

—

—

—

—

3.8

640

499

11.0

45

0.6

6.2

—

—

680

1.7

400

790

9.2

86

675

9.3

73

7.4

398 690

9.4

73

10.4

38

—

—

—

—

0.2

1

—

228

6.7

—

670

—

10.4

—

400

3.38

—

—

—

350

260–360

500

350

600

450

400

700

700

500

450

500

350

350

600

**pH**

**Carbon (g/kg)**

**Nitrogen (g/kg)**

**Carbon/ nitrogen ratio**

**Phosphorus (g/kg)**

**Potassium (g/kg)**

**Ash (%)**

**CEC (mEq/100 g)**

**Pyrolysis temperature (°C)**

*Enhancement of Soil Health Using Biochar DOI: http://dx.doi.org/10.5772/intechopen.92711*

### *Enhancement of Soil Health Using Biochar DOI: http://dx.doi.org/10.5772/intechopen.92711*

*Applications of Biochar for Environmental Safety*

tar and also in the production of hydrogen [3].

between the microorganisms and the plants [5].

environment [6].

the natural environment. It has also been used for the purpose of heavy metal diges

tion, pollutant immobilization as well as a supplement to composting and methane fermentation process [1, 3]. Recently, biochar is being used in pyrolytic filtering of

The presence of organic matter and nutrients in biochar is vital because the nutrients provide basic mineral supplements for the soil. Therefore, the amendment of soil with biochar increases the soil's pH, cation-exchange capacity (CEC), total nitrogen, organic carbon and conductivity. It has been reported that the fate and toxicity of heavy metals have been reasonably reduced due to the amendment of soil with biochar [4]. Furthermore, the porosity, large surface area and absorbance potential have made biochar a medium for soil nutrient improvement. Likewise, biochar also acts as a suitable habitat for soil microorganisms to thrive, alongside the support by roots of leguminous plants that aid the symbiotic relationships

Biochar has also been known to decrease the tensile strength of the soil because of its porosity and ability to create air pores within the soil, thus reduc

**2. Biochar properties that enhance environmental safety**

ment of certain properties possessed by the biochar product [7, 8].

and their pH. Some of the properties of biochar are shown in **Table**

processes at the point of production of the biochar are also indicated.

that are supplemented with biochar have a very high degree of absorption.

**1** describes the porous nature of a typical biochar.

chemical composition of the biochar itself [3, 9].

ing soil compaction. With this development, biochar can be used as a sustainable tool for agricultural soil development. High crop yields can be produced with the use of biochar without necessarily depleting essential nutrients from the

Biochar can be produced from varieties of materials ranging from sewage, farm produce, energy crops and agricultural waste or residues. Other materials used for biochar include forest wastes like conifer barks, sawdust pellets, paper and moss. After biochar is produced, the quality of the biochar is determined by the assess

Typically, biochars contain stable organic compounds where the carbon content

properties determine the level of biochar quality. The temperatures of the pyrolytic

The pH is either neutral or alkaline. The alkaline pH sometimes results from the biomass pyrolysis of high temperature. The increase in the temperature of the soil containing the biomass has a resultant effect on the alkalinity of the biomass [10]. However, at lower temperatures, high ion-exchange biochars are produced. The cation exchange capacity which determines nutrient absorption indicates a rise in temperature at every rise in the cation exchange capacity of the soil biomass [11]. It is as a result of these physicochemical properties that make biochars qualify as good soil carbon sequesters and soil remediation agents [3, 12]. Furthermore, soil types

Biochar has a predominantly condensed aromatic structure that is known to be highly resistant to microbial decomposition. The porosity of the biochar adds to the water retention capacity of the soil and increases the soils ability to form aggregates

The properties usually considered at the post-production stage of biochar include the chemical composition, porosity and stability. However, at the point of production, the chemical composition can be manipulated by the type of substrate used in the biochar preparation and the composition of the substrate determines the

may be within the range of 50 to 90% and volatile content at 10 to 50% [2, 10]. Biochar seldom undergo microbial degradation because of their carbonized nature




**1**. These

**144**

[13]. **Figure**


*exchange capacity) of the suitable biomass was determined.*

### **Table 1.**

*Selected properties of biochar and the respective temperatures of pyrolytic processes.*

**Figure 1.** *The porous nature of biochar (Burrell et al. [14]).*
