2. Sewage sludge, horse manure, chicken manure, and vermicompost: an overview

#### 2.1. Municipal sewage sludge

through increasing nutrient availability and water holding capacity, total pore space, aggregate stability, erosion resistance, temperature insulation, and decreasing soil density. Antonious [1] reported that sewage sludge (SS) and chicken manure (CM), that must be disposed, are

Tomatoes (Solanum lycopersicum, formerly Lycopersicon esculentum Mill) belong to the Solanaceae family. Tomato has achieved a remarkable status among other vegetables because of its rich nutritional composition and widespread consumption. It is one of the major vegetable crops grown in almost every country of the world. Fresh tomato fruits contain several nutritional compounds including vitamin C (ascorbic acid) and minerals [2] and have been shown to reduce the risks of cardiovascular diseases and certain types of cancer, such as prostate, lung, and stomach cancers [3]. Accordingly, enhancing the nutritional value of fresh tomatoes and tomato products require frequent investigations to evaluate the influences of agricultural practices, such as the use of fertilizers, organic soil amendments, and the environmental conditions on tomato yield and fruit quality. It was demonstrated that increasing N fertilization under field conditions reduced the fruit vitamin C concentration [4]. This is due to the fact that the high N concentration in the fertilizers favors plant leaf area development, thereby lessening light penetration in the canopy and fruit vitamin C development. Similarly, the negative effects of N application on vitamin C contents occur in other vegetables such as potatoes [5]. The typical taste of tomato is mainly attributed to soluble sugars, organic acids and volatile compounds. Sugars are important macronutrients of the human diet and plants. During tomato ripening total soluble solids (TSS), such as sugars (fructose and glucose) are found to be predominant in domesticated tomato fruits. Tomato possesses a wide range of bioactive compounds as a pool of antioxidants that have positive effects on health, associated with their anti-carcinogenic and antiatherogenic potential [6]. These bioactive compounds include carotenoids (vitamin A), ascorbic acid (vitamin C), phenolic compounds, and tocopherols (Vitamin E), which are at higher concentrations in the skin followed by seed and pulp fractions [7]. In addition, concentrations of bioactive compounds in tomato fruit are significantly influenced by tomato genotype [8, 9], environmental factors and agricultural techniques [10]. Regarding tomato phenolic compounds content, chlorogenic acid and rutin have been found to be the most important flavonoids in tomato. Butta and Spaulding [11] found high concentrations of total phenols in tomato fruits at the early stages of fruit development, then phenols concentration declined rapidly during fruit ripening, although other authors have shown that the content of total phenols remained stable during ripening [12].

The literature review verified the potential of biochar, a product of wood pyrolysis, applications for improving N input in agricultural systems, while indicating the needs for long-term field studies to better understand the effect of biochar on biological N2 fixation. When biomass, such as wood, manure, or leaves, is heated in a closed container with little or no available air, this process is known as pyrolysis. Research results indicated that the conversion of biomass into biochar can not only result in renewable energy (synthetic gas and bio oil), but also decrease the content of CO2 in the atmosphere [13]. When biochar was used in column leaching experiments to assess its ability to hold nutrients, results indicated that biochar effectively reduced the total amount of nitrate (NO3), ammonium (NH4), and phosphate in leachates by 34, 35, and 21%, respectively, relative to native soil alone [14]. The adsorption of N by biochar particles decreases NH4 and NO3 loss during composting and after manure applications, providing a mechanism for releasing nitrogen fertilizers in a slow release process [15]. Biochar is a porous and

excellent fertilizers.

46 Agricultural Waste and Residues

Municipal sewage sludge (SS), also known as biosolids (Figure 1) is derived from wastewater treatment plants in which wastewater, primarily derived from domestic sources or discharges from commercial and industrial enterprises. Most of these enterprises carry out pretreatments prior to discharging wastes into the conventional community sewer system. As a result of pretreatment, total fertilizer nutrient concentration rarely exceeds 10% in most manure sources and frequently is a fraction of that. Commercial fertilizers usually contain about 30% nutrients by weight. Low nutrient concentration increases the time and cost of transportation and land application [22]. Nutrients in most commercial fertilizers are designed to be rapidly available to crops when applied to the soil. Whereas, the organic nitrogen fraction of manure reduces the availability and predictability of the manure as a nitrogen source because the availability of organic nutrients is dependent on soil microbial activity. In addition, the chemistry of manure makes inorganic nitrogen in manure prone to volatilization losses when it is surface applied. Successful use of organic manure fertilizer requires adjusting application rates to account for reduced nutrient availability.

Figure 1. Metropolitan wastewater treatment plants in Louisville, Kentucky turned municipal sewage sludge into package of organic fertilizer "Louisville green" available in stores.

used to control protozoan parasites and to enhance poultry weight gain. Despite this, CM can be effective sources of essential plant nutrients such as N and P, and as a source of soil organic carbon. The phytotoxicity in some plants grown in CM amended soils indicated the need for further trials to reduce its toxic impact through composting and/or vermicomposting to improve

Biochar and Animal Manure Impact on Soil, Crop Yield and Quality

http://dx.doi.org/10.5772/intechopen.77008

49

Recycling agricultural waste for use in crop production has become a vital component of organic agriculture. In the US, about 95% of food scraps and 42% of yard waste (Figure 3A) are currently used in landfill [27]. There are some concerns about the varying composition of yard waste by region and by season. The Department of Environmental Protection in Pennsylvania [28] estimated that, during the summer, grass clippings constitute up to 50% of municipal waste. In the fall, leaves make up 60–80% of the material in this category. Many communities ban dumping and outdoor burning of plant materials such as leaves and tree branches. Accordingly, composting and mulching have become a management way to recycle yard waste as economical soil amendment to improve garden soils and growing plants.

The interaction of earthworms with microorganisms and other fauna within a decomposer, especially designed for this incubation process, produces a product known as vermicomposting (Figure 3B). Vermicomposting accelerates the stabilization of organic matter (OM) and its physical and biochemical properties. Physical participation in degrading organic substrates results in fragmentation, thereby increasing the surface area of action, turnover and soil aeration. The degradation of OM is carried out by enzymatic secretions by microorganisms. This process is enriched by transport of inorganic and organic materials. The benefit of vermicomposting is the recycling of organic wastes, like animal wastes [29, 30], crop residues [31], and industrial wastes [32–35] for use as N fertilizer. Anoop et al. [35] concluded that cow

nutrient content and reduce the phytotoxicity to growing plants [19].

Figure 2. Chicken manure waste turned into package of organic fertilizer available in stores.

2.3. Yard waste compost, vermicompost, and horse manure

2.3.1. Yard waste compost

2.3.2. Vermicomposting or worm castings

Organic manure products sold as commercial crop fertilizers have nutrients concentrations typically vary spatially and over time within the manure storage facilities making it hard to meet fertilizer needs. Accordingly, calculating the recommended rate of organic fertilizer application is a challenge when farmers follow the label instructions. Should farmers apply a rate that on average supplies the target nutrients rate or use a rate of application that insures the entire field gets at least the needed fertilizer rate? The first strategy insures portions of the field will have nutrient deficits, an economic liability to the farmer; the second strategy maximizes yield but also insures that part of the field will have nutrient excess and a water quality liability [22]. Biosolids have become less contaminated with trace metals and organic compounds [23]. In wastewater treatments plants solids are removed during primary and secondary treatment. SS product is usually incinerated, landfilled or further treated. Further treatment may consist of digestion, composting or alkaline stabilization. After treatment, this material is called biosolids. Biosolids contain inorganic materials, plant nutrients, trace elements, and organic compounds.

#### 2.2. Chicken manure

Tremendous expansion in the poultry industry occurs worldwide [18]. Due to the fast expansion in the poultry industry, production of poultry manure (Figure 2) has increased significantly. Chicken manure (CM), which is the most abundant poultry manure, is a mixture of feces, waste feed, feathers and bedding material, and contains essential plant nutrients making it an organic source of nutrients. For example, N, P, and potash (K) are approximately 8.5% of the weight of poultry litter. Though beneficial as an organic amendment, the huge quantities being produced in poultry farms have resulted in unplanned disposal of this manure to the soil in some cases, where it poses environmental challenges like eutrophication, air pollution, emission of greenhouse gasses and production of phytotoxic substances [19, 24, 25]. On the other hand, animal manure like poultry manure have been found to contain potentially harmful trace elements like arsenic, copper and zinc, which originate from the chemicals used to treat diseases in commercial chicken production [25]. Broiler chicken litter is a source of trace elements that can potentially accumulate in the soil after repeated applications and this is why it is important to test for poultry manure composition before direct application to farm lands. In addition, arsenic (As) which is a severe carcinogenic compound [26] is a feed additive in conventional raised broilers

Biochar and Animal Manure Impact on Soil, Crop Yield and Quality http://dx.doi.org/10.5772/intechopen.77008 49

Figure 2. Chicken manure waste turned into package of organic fertilizer available in stores.

used to control protozoan parasites and to enhance poultry weight gain. Despite this, CM can be effective sources of essential plant nutrients such as N and P, and as a source of soil organic carbon. The phytotoxicity in some plants grown in CM amended soils indicated the need for further trials to reduce its toxic impact through composting and/or vermicomposting to improve nutrient content and reduce the phytotoxicity to growing plants [19].

#### 2.3. Yard waste compost, vermicompost, and horse manure

#### 2.3.1. Yard waste compost

Organic manure products sold as commercial crop fertilizers have nutrients concentrations typically vary spatially and over time within the manure storage facilities making it hard to meet fertilizer needs. Accordingly, calculating the recommended rate of organic fertilizer application is a challenge when farmers follow the label instructions. Should farmers apply a rate that on average supplies the target nutrients rate or use a rate of application that insures the entire field gets at least the needed fertilizer rate? The first strategy insures portions of the field will have nutrient deficits, an economic liability to the farmer; the second strategy maximizes yield but also insures that part of the field will have nutrient excess and a water quality liability [22]. Biosolids have become less contaminated with trace metals and organic compounds [23]. In wastewater treatments plants solids are removed during primary and secondary treatment. SS product is usually incinerated, landfilled or further treated. Further treatment may consist of digestion, composting or alkaline stabilization. After treatment, this material is called biosolids. Biosolids

Figure 1. Metropolitan wastewater treatment plants in Louisville, Kentucky turned municipal sewage sludge into pack-

contain inorganic materials, plant nutrients, trace elements, and organic compounds.

Tremendous expansion in the poultry industry occurs worldwide [18]. Due to the fast expansion in the poultry industry, production of poultry manure (Figure 2) has increased significantly. Chicken manure (CM), which is the most abundant poultry manure, is a mixture of feces, waste feed, feathers and bedding material, and contains essential plant nutrients making it an organic source of nutrients. For example, N, P, and potash (K) are approximately 8.5% of the weight of poultry litter. Though beneficial as an organic amendment, the huge quantities being produced in poultry farms have resulted in unplanned disposal of this manure to the soil in some cases, where it poses environmental challenges like eutrophication, air pollution, emission of greenhouse gasses and production of phytotoxic substances [19, 24, 25]. On the other hand, animal manure like poultry manure have been found to contain potentially harmful trace elements like arsenic, copper and zinc, which originate from the chemicals used to treat diseases in commercial chicken production [25]. Broiler chicken litter is a source of trace elements that can potentially accumulate in the soil after repeated applications and this is why it is important to test for poultry manure composition before direct application to farm lands. In addition, arsenic (As) which is a severe carcinogenic compound [26] is a feed additive in conventional raised broilers

2.2. Chicken manure

48 Agricultural Waste and Residues

age of organic fertilizer "Louisville green" available in stores.

Recycling agricultural waste for use in crop production has become a vital component of organic agriculture. In the US, about 95% of food scraps and 42% of yard waste (Figure 3A) are currently used in landfill [27]. There are some concerns about the varying composition of yard waste by region and by season. The Department of Environmental Protection in Pennsylvania [28] estimated that, during the summer, grass clippings constitute up to 50% of municipal waste. In the fall, leaves make up 60–80% of the material in this category. Many communities ban dumping and outdoor burning of plant materials such as leaves and tree branches. Accordingly, composting and mulching have become a management way to recycle yard waste as economical soil amendment to improve garden soils and growing plants.

#### 2.3.2. Vermicomposting or worm castings

The interaction of earthworms with microorganisms and other fauna within a decomposer, especially designed for this incubation process, produces a product known as vermicomposting (Figure 3B). Vermicomposting accelerates the stabilization of organic matter (OM) and its physical and biochemical properties. Physical participation in degrading organic substrates results in fragmentation, thereby increasing the surface area of action, turnover and soil aeration. The degradation of OM is carried out by enzymatic secretions by microorganisms. This process is enriched by transport of inorganic and organic materials. The benefit of vermicomposting is the recycling of organic wastes, like animal wastes [29, 30], crop residues [31], and industrial wastes [32–35] for use as N fertilizer. Anoop et al. [35] concluded that cow

dung and biogas plant slurry can be used as a raw material in vermicomposting. The NPK elements and C/N ratio of vermicompost revealed its agronomic value as organic soil conditioner. Accordingly, many investigators reported that vermicompost has important properties that can be explored as a new technology for converting organic wastes into a product rich in plant nutrients [35].
