Biochar Applications in Agriculture and Environment Management

Salt-affected soils occur in the areas where excess dissolved mineral salts accumulate in the root zone that crop yields are adversely affected from the salts released by weathering of rock or those initially present in the soil-forming materials. In addition, evaporation and transpiration processes, due to high temperatures and droughts, can cause salt movement with capillary action inducing its accumulation in surface soil. Excess amounts of salts cause adverse effects on the physical and chemical properties of soil, microbiological processes and food security. Biochar produced from rice husk (RH) under the pyrolysis condition (400–500 °C) from a retort designed to produce laboratory quality biochar that is easy for farmers to use in order to promote self- sustaining biochar production. This study aimed to explore the use of rice husk biochar as a soil amendment in order to solve the salt- affected soil problems. The study area was Bung O sub- district, Kham Thale So district where the critical of salt-affected soil and drought area in Nakhon Ratchasima, Thailand. The results indicated that adding RH biochar with organic fertilizer into soil can improve both physical and chemical properties in every parameter. Particularly, the soil became less alkalinity. The results also showed an increased ion exchange capacity, higher amount of major and minor soil nutrients and the reduced amount of all sodium in the soil in every parameter. This included the absorption rate of sodium in the soil, the conductance of the soil, all of the amount of sodium in the soil, and the increasing amount of exchangeable magnesium and the amount of exchangeable calcium. The two elements contained positive ions which could replace the sodium ions in the salty soil making the soil less salty.

Society currently faces global environmental challenges of the burning of waste plants reside which demand innovative, interdisciplinary and complex solutions. In India about 500 million tons agricultural and agro-industrial residues are being generated annually in the country. A major amount of this agricultural residue farmers treats as waste, are burn in field itself. Hence, there is need to combat these problems through a sustainable management system, which will revive depletion of waste generated from agriculture itself. Conversion of this agricultural waste into biochar through pyrolysis could be a positive solution for minimizing agricultural waste. Production of biochar also offers many opportunities for enhancing soil Physico-chemical characteristics and carbon sequestration. However these characteristics alter with different factors like type and temperature of pyrolysis, biomass holding time. In the present chapter the detailed information of pyrolysis techniques and their impact on soil fertility are discussed.

The unbridled industrialization and unrestrained expansion of modern textile facilities combined with a deficiency of adequate treatment provisions have escalated the discharge of toxic effluents rich in carcinogenic pollutants such as dyes. As a consequence, there is an alarming need for the development of financially suitable and highly efficient treatment options to protect the immaculate ecosystems, natural resources, and human health. In this respect, adsorption-based treatment options have attracted widespread attention as eco-friendly and cost-effective approach. Biochar has propelled itself to the forefront of the scientific community as a highly economical sorbent with great adsorption capabilities. Notably, biochars provide a win-win strategy by simultaneously utilizing the waste biomass during its production and a great adsorbent for pollutant removal. Although biochars have been applied for the treatment of various dyes, there have been very few reports of its application for Congo red (CR) dye. In this book chapter we analyze the application of biochar for dyes with particular focus on CR. We try to practically understand the mechanism of interaction between biochar and CR molecules (a model anionic azo dye) by elucidating an experimental case study. The case study will provide valuable insights into the importance of the utilization of locally available bio waste for economic biochar production and the mechanism of removal of anionic dyes through biochars. In brief, the adsorptive removal of CR was investigated using Arjun fruit biochar (AFB) derived from the fruit of locally grown Terminalia arjuna. The sorptive removal of CR on AFB was investigated under the following operational conditions (pH, 2–12; biochar dosage, 4–14 g/L; temperature, 30–60 °C; and contact time, 30–480 min). The sorption behavior of CR was well described through the Langmuir monolayer model (R² = 0.9985) and pseudo-second order kinetics (R² ≥ 0.9977) for all tested CR levels (20–100 mg/L). The results of thermodynamic analysis revealed that the sorption of CR onto AFB proceeded favorably and spontaneously.

Soil contamination with heavy metals has become a serious concern. Due to their non degradable nature, speciation and bioavailability to the living organisms, heavy metals are prone to enter the food chain. Heavy metals are also known as trace elements because they are found in trace concentration into the environment (<10 ppm or ppb). Accumulation of heavy metals and metalloids such as As, Pb, Cd, Hg, Se, Cd in soil is an issue of growing concern due to their lethal, carcinogenic, mutagenic effects, and multiple organ dysfunction in the living organisms. However some heavy metals like Cr, Zn, Bo, Cu, Co, Fe, Mn and Ni are necessary in trace amount for different biochemical functions of animal and plant system. Rapid urbanization and increasing industrialization leads to the accumulation of heavy metals into the soil. Contaminated soil can causes many physiochemical and biochemical changes into plants resulting in reduced growth, affecting the yield which eventually leads to food insecurity. Many strategies like isolation, immobilization, extraction, phytoremediation, soil washing, etc. are used for remediation of heavy metal contaminated soil.

Biochar has been applied to soil as a novel carbon rich material for heavy metal remediation. Biochar is a solid product with porous structure, obtained when biomass is thermo-chemically treated in a closed container in oxygen-limited environment. Physicochemical properties of biochar made it a potential candidate for long term carbon storage. Low production cost, high cation exchange capacity, pH, surface functional groups and porous structures are some of the intrinsic properties of biochar making it a choice as an adsorbent for heavy metal remediation from soil. Biochar has capacity to make complex with heavy metals present in soil, which reduce their bioavailability.

Land degradation and climate change are important associated processes necessitating appropriate management options to solve alarming food security threats in developing nations. Biochar produced from plant matter and applied to the soil has become increasingly recognized to address multiple contemporary concerns, such as agricultural productivity and contaminated ecosystem amelioration, primarily by removing carbon dioxide from the atmosphere and improving soil health. Biochar is an anaerobic pyrolysis product derived from organic material, resistant to easy degradation and stored carbon in the long-term in the terrestrial ecosystem and capable of reducing greenhouse emission from soil to the atmosphere. Further, it has the potential to adsorb and degrade heavy metals accumulated in the industrial and contaminant sites. The different source of biochars and graded levels of application has positive and negative effects on crop yield under different soil types. Most of the results in biochar are a greenhouse and laboratory-based experiment and lack of field experimental evidence in the semiarid environment. In this chapter need for biochar production, characterization, soil health changes, environmental clean-up potential, and crop yield dynamics under changing climate and research on biochar in the near future will be focused on sustainable crop and environmental management.

Soil contamination due to heavy metals has become a great concern nowadays. The main reasons for soil contamination are both natural as well as anthropogenic. Natural processes like volcanic eruption, weathering of rocks, landslides and soil erosion while anthropogenic involves several activities like smelting, mining, application of agrochemicals (pesticides, herbicides and fertilizers) and industrial wastes. Heavy metals pollution has a direct influence on the fertility of agricultural soils. The removal of heavy metals from soil is very difficult as it stored in the environment for a long time, because of its persistent nature. Several in-situ bioremediation technologies are used for removal of heavy metals from the environment. Out of that in-situ biochar application is one of the prominent technologies for remediation of heavy metals and it was found to be effective in reducing the mobility of heavy metals in soils. Biochar effectively adsorbs heavy metals and decreases bioavailability and toxin-induced stress to the biotic component of soil. In this chapter, the emphasis has been given on heavy metal pollution and types of biochar used for remediation of heavy metals from the soil and water.

Global warming and associated climate change are becoming a threat to almost all the ecosystems on the earth. According to the intergovernmental panel on climate change (IPCC) special report 2019, the global mean surface (land and ocean) temperature has been increased by 0.87 °C while mean of land surface air temperature has increased by 1.53 °C since 1850–2015. Climate change is affecting food security and human life due to warming, changing precipitation patterns, and the greater frequency of some extreme events. The main cause of global warming is the continuous increase in the atmospheric concentration of greenhouse gases (GHGs) like CO₂, CH₄, N₂O and fluorinated gases due to several anthropogenic activities. Therefore, reducing the increasing concentration of GHG is necessary to slow down global warming and climate change. Among several options of greenhouse mitigation, application of biochar into the soil is gaining popularity due to several advantages over other options. Biochar is a highly stable form of carbon derived from pyrolysis of biomass at relatively low temperatures. Application of biochar into the soil has been reported to provide multiple benefits like increase in crop yield, nutrient and water use efficiency and several environmental benefits. Recalcitrant nature, relatively higher carbon content and easily available feedstock make biochar a highly sustainable and quick option for carbon sequestration into the soil. Biochar application into the soil not only helps in carbon sequestration but also provides a better option for managing agricultural residues. The application of biochar has also reported for reducing a considerable amount of methane and nitrous oxide emission from the agricultural field due to its priming effect on the soil. Biochar yield, physical properties, and carbon content varies with the type of feedstock and pyrolysis condition. Therefore, the rate of carbon sequestration and mitigation of greenhouse gas is also highly variable, however, the biochar application ultimately leads to a positive contribution towards climate change mitigation. However, most of the reported benefits are confined to laboratory and field trial at institute level, widespread adoption of biochar on farmer’s field is still lacking. In the present chapter, all the aspects of biochar towards carbon sequestration and greenhouse mitigation have been well discussed.

Cyanobacterial soil crusts (CSCs) are unique microhabitats in desert soil plays a significant role in stabilization of soil surface and provide favourable conditions for the establishment of vascular plants. The CSCs types and its distribution mainly depend up on the locality and climatic factors of the region. They help in retaining soil particles, nutrients, moisture and also add up carbon and nitrogen to the nutrient poor soils. The natural or anthropogenic intervention exerted immense pressure on the crusts community and diversity; leads to disturbed or distressed CSCs. Currently military use of the deserts have destroyed the fragile ecology of these CSCs and delay the time of recovery to reach functional state. To stabilize and rehabilitate the disturbed CSCs, a number of strategies successfully tested and implemented in small scale, some of them are artificial stabilization, resource augmentation and cyanobacterial inoculants. Biochar coupled rehabilitation of CSCs could be effective and sustainable approach for the stabilization of desert soils. Small scale biochar production would be helpful not only reducing the cost of rehabilitation but also help in providing livelihood to the local people.

The utilization of biochar as an amendment to improve soil health and the environment has been a catalyst for the recent global enthusiasm for advancing biochar production technology and its management. Biochar is simply carbon rich charcoal-like substance which is created by heating biomass (organic matter) in limited oxygen condition, through a process known as pyrolysis. Locally available weed biomass which is not economically important and caused crop loss can be used as an important source of biomass for preparation of biochar. Biochar is able to ameliorate soil acidity as well as it is also able to increase the soil fertility. Biochar reduces leaching of soil nutrients, increases soil structure and pH, reduces dependency on artificial fertilizers, enhances nutrient availability for plants, increases water quality of runoff, reduces toxicity of aluminum to plant roots and microbiota and thus reducing the need for lime, reduces bioavailability of heavy metals, thus works as bioremediation and decreases N₂O and CH₄ emissions from soils, thus further reducing GHG emissions. Employment of biochar as a specialized soil amendment provides a practical approach to address the anticipated problems in the agronomic and environmental sectors. Incorporating huge quantity of biochar into soils provides numerous agricultural benefits, which this special paper examines. But, there is no concrete compilation yet how to apply biochar at farm level. This paper discusses on several factors related to biochar that need to be considered for maximising the soil amelioration and soil quality benefits from the use of biochar.

The utilization of agricultural wastes are considered to be the important step in environmental protection, energy structure and agricultural development. The agricultural straw disposition of agricultural wastes not only results in environmental pollution, but also waste a lot of valuable biomass resources. Biochar the viable organic amendment product derived from organic sources and store carbon on a long term basis in the terrestrial ecosystem and also capable of reducing greenhouse gases (GHG) emission from soil to the atmosphere to combat climate change and sustain the soil health with sustainable crop production. The role of biochar in developing a sustainable agriculture production system is immense and so is its potential in mitigating climate change, which stands much beyond its uses in agriculture. The addition of biochar to soils resulted, on average, in increased above ground productivity, crop yield, soil microbial biomass, rhizobia nodulation, plant K tissue concentration, soil phosphorus (P), soil potassium (K), total soil nitrogen (N), and total soil carbon (C). The effects of biochar on multiple ecosystem functions and the central tendencies suggest that biochar holds promise in being a win-win-win solution to energy, carbon storage, and ecosystem function. However, biochar’s impacts on a fourth component, the downstream non target environments, remain unknown and present a critical research gap.

Biochar, a co-product of the pyrolytic conversion of biomass and biowastes to biofuel is a carbon rich recalcitrant material. It has received much attention in the recent times for its prospective application in various fields viz. as a soil amendment for improving the physical, chemical, and biological qualities of agricultural soils, as an adsorbent for removal of various organic and inorganic contaminants in water, for removal of pesticides residues in soil, for correcting soil acidity, as a precursor for chemical synthesis, for industrial applications such as supercapacitor application, as a support material for fuel cells, for enhancement in biogas generation to name a few. In addition to all these, biochar’s green-house gas mitigation potential, and C-sequestration potential are two most significant attributes that has made biochar a suitable component for SDGs. Further, these applications have made biochar as one of the most researched topics in recent times. The ease of biochar production is also another advantage which can be beneficial for farmers even with a marginal land holding. In this chapter, an attempt has been made to discuss the role of biochar in management of agricultural soils, as well as its vast environmental application possibilities.

The extensive use of chemical fertilizers in agriculture have long term deleterious impact such as leading salinity, decline fertility of soil with fast growth of agricultural production and it is predicted that the fertilizer use to continue increase in the coming years. With current scenario, there has been keen interest on biochar, produced from various crop residues with multiple environmental applications such as soil amelioration, pollutants removal and carbon sequestration. Biochar has several unique properties like high alkaline pH, fixed carbon content, stability against decay, water holding capacity and cation exchange capacity, which makes it an efficient, cost-effective and environmentally-friendly material. Many study showed the effectiveness of biochar amendments in soil i.e. nutrient status improvement, increases soil porosity, soil pH, soil moisture-holding capacity and boost the growth of beneficial plant growth promoting microbial community.