Biochar Production from Plant Residues: A Sustainable Approach for Carbon Sequestration and Soil Fertility Improvement

Biochar production has gained significant attention lately due to its potential to sequester carbon, improve soil fertility and mitigate climate change. Various production technologies have been developed to convert biomass into biochar, each with its unique characteristics and advantages. This review provides a comprehensive overview of the current biochar production technologies aiming to synthesize existing knowledge and identify research gaps with a focus on their potential to contribute to the United Nations Sustainable Development Goals (SDGs) 2, 12, 13 and 15. The scope of this review encompasses various biochar production techniques including slow pyrolysis, fast pyrolysis, gasification and torrefaction. The effects of production conditions such as temperature, residence time, and feedstock types on biochar properties and yields are discussed. The prospects of using biochar in the agricultural system were discussed. Additionally, challenges and opportunities associated to scaling up biochar production technologies are highlighted. The findings of this review have implications for the development of sustainable biochar production practices and environmental management strategies.

In many nations across the world, farming is an important industry. Sustainable farming methods known as zero tillage systems entail planting seeds without tillage, which disturbs the soil. With this approach, crop residues from the previous year are left on the earth's surface and new plants are planted straight into the undisturbed soil, as opposed to plowing. This method aids in preserving the structure of the soil, decreasing soil erosion, retaining more water, and enhancing soil health. Farmers can benefit from enhanced soil health, decreased soil erosion, higher crop yields, and environmental sustainability by implementing sustainable farming practices. By limiting soil disturbance and shielding soil particles from the elements, this system aids in the reduction of soil erosion. Additionally contributes to improved soil structure, which raises soil fertility, and helps hold onto soil moisture, which lessens the need for irrigation. The amount of tillage and fuel used in zero-tillage systems can be less than in conventional tillage methods. In comparison to traditional tillage methods, systems require less fuel and tillage, which can save farmers money and lessen their carbon footprint. This is true because these systems raise soil organic matter levels, which in turn raise soil nutrient availability and improve soil fertility. Moreover, zero tillage systems can increase water retention in the soil, which can enhances crop growth and yield by improving soil structure and moisture retention, while also reducing weed competition. By reducing soil erosion, conserving soil moisture, and improving soil health, these systems help to promote environmental sustainability. Also reduce greenhouse gas emissions by reducing fuel usage and sequester carbon in the soil through the accumulation of crop residues. Therefore, farmers should adopt zero-tillage systems to enhance their productivity, reduce costs, and promote environmental sustainability.

Chapter 16 - Legume-based inter-cropping to achieve the crop, soil, and environmental health security

Biochar, a carbon-rich soil amendment produced by pyrolysis of biomass, has emerged as a promising tool for enhancing soil health, agricultural productivity, and carbon sequestration. Biochar can be produced from a wide range of biomass feedstocks, including agricultural residues (e.g., crop straws, husks, and shells), forestry waste (e.g., wood chips and sawdust), and organic waste materials. However, the use of forestry waste and organic waste materials has gained attention as a means to valorise these resources and reduce their environmental impact This review explores the production, properties, and applications of biochar in agriculture and environmental management. Biochar's unique characteristics, such as high porosity, large surface area, and stable carbon structure, contribute to its potential benefits in soil fertility improvement, water retention, nutrient cycling, and greenhouse gas mitigation. The review also discusses the challenges and opportunities associated with biochar utilisation, including feedstock availability, production technologies, and socio-economic considerations. The findings revealed that biochar application increased crop yields by an average of 10%, with greater benefits observed in acidic and sandy soils. Another study reported an average crop yield increase of 11% with biochar application, with the most significant improvements observed in tropical and subtropical regions. Another study reported an average reduction of 31% in N₂O emissions with biochar application, with the greatest reductions observed in acidic soils and soils with high nitrogen input. The study concluded that biochar has emerged as a promising tool for promoting soil health, enhancing agricultural productivity, and mitigating climate change. The unique properties of biochar, such as its high porosity, large surface area, and stable carbon structure, contribute to its potential benefits in improving soil physical, chemical, and biological properties, increasing crop yields, and sequestering carbon in soils. Furthermore, it highlights the need for further research to optimise biochar production and application strategies for specific soil types and cropping systems. Biochar's multifaceted benefits position it as a valuable tool in the pursuit of sustainable agriculture and climate change mitigation, paving the way for a greener planet.

A critical review on production, modification and utilization of biochar

Mineral fertilizers have been associated with the accelerated decomposition of organic matter in the soil. This rapid decomposition primarily affects organic materials such as plant residues and other organic substances present in the soil. Biochar, produced by the pyrolysis of biomass, offers a sustainable solution to enhance soil fertility and crop productivity. Biochar has a one of a kind potential to improve soil health and counteract global climate change. Its distinct qualities, such as high carbon content and the potential to promote soil health, make it an efficient, environmentally friendly and cost-effective material for overcoming global food security and increasing temperatures. Biochar can be produced using a variety of biomass materials and at various temperatures, resulting in a wide range of variations in the final product. Because of variations in its physicochemical attributes, such as microporosity, surface area and pH, biochar can be customized for specific applications. The pyrolysis temperature, heating rate, residence time, and biomass used during production all have a strong influence on the structural configuration and elemental composition of biochar. According to research, biochar produced at high pyrolysis temperatures has high ash, phosphorus, and potassium concentrations. Furthermore, many important macro and micronutrients, such as calcium, magnesium, iron, and zinc, have been found to be positively associated with increasing temperature. Biochar produced at low pyrolysis temperatures, on the other hand, provides relatively more available nutrients in the soil and can help to reduce carbon dioxide emissions. Biochar produced at high pyrolysis temperatures has a stronger affinity for organic contaminants due to its increased surface area, hydrophobicity, microporosity, high pH, and low dissolved organic carbon. It is important to note that the properties of biochar should be thoroughly assessed before application due to the wide variability of biomass resources and pyrolysis conditions. Furthermore, biochar production should be tailored to the intended application in soil to maximize its efficacy.

Soil has a major role in sequestering atmospheric CO2. This has further benefits and potential to improve soil fertility and food production, mitigate climate change, restore land degradation, and conserve ecosystem biodiversity. However, its health is increasingly being threatened by the growing population, land degradation and climate change effects. Despite its importance, soil organic carbon (SOC) is understudied in the tropics. This paper reviews how managing forests in tropical ecosystems can benefit SOC sequestration and land restoration. Sequestered SOC has the potential to improve soil fertility, as well as to reduce both land degradation and atmospheric CO2 emissions. It further improves soil structure, aggregation and water infiltration, enhances soil faunal activity and boosts nutrient cycling (C, N, P and S). Managing forest ecosystems is crucial to boost C sequestration, mitigate climate change and restore degraded lands, besides other ecosystem services they provide. Apart from managing natural forests and planted forests, afforesting, reforesting marginal or degraded lands especially when associated with specific practices (organic residue management, introducing nitrogen-fixing species) boost C storage (in both soil and biomass) and foster co-benefits as soil health improvement, food production, land restoration and mitigation of climate change. Improved soil health as a result of sequestered C is confirmed by enhanced physical, biological and chemical soil fertility (e.g., sequestered C stability through its link to N and P cycling driven by soil biota) which foster and sustain soil health.

Biochar is a natural carbon-rich material that when applied to soil, can improve soil fertility and water taking-up capacity. The use of biochar is useful in organic agriculture, indirectly preventing the release of CO2 into the atmosphere. The objective of this work was to produce and analyze the Physico-chemical properties of corncob biochar from slow pyrolysis that were related to the improvement of the soil for cultivation. Biochar was produced at 500 °C and 60 min of pyrolysis temperature and residence time. At this condition, yield and some properties of biochar were most suitable. Moisture, volatile, fixed carbon, and ash contents the biochar obtained were 1.8%, 33.1%, 59.0%, and 6.1%, respectively, with an average biochar yield of nearly 34%. Carbon, hydrogen, nitrogen, oxygen and sulfur content achieved were 71.5%, 3.1%, 0.9%, 10.3% and 0.03%, respectively. Highest heating value and pH of the biochar were 24.85 MJ/kg and 8.59. The surface area of 8.1999 m2/g, cumulative absorption value, and pore of 0.009134 cm3/g and 65.022 Å were obtained. They were found to increase with increasing pyrolysis temperature and residence time. The electrical conductivity and cation exchange capacity obtained were 1,340 µS/cm and 123.17 cmol/kg. Biochar obtained here appeared to have good properties for soil improvement.

Mixed Solid Municipal Waste-Based Biochar for Soil Fertility and Greenhouse Gas Mitigation

Aims: This study aimed to determine the effectiveness of various ameliorant sources in enhancing NP uptake and the productivity of sweet corn (Zea mays L. saccharata) in sandy soil. Study Design: The study used a randomized block design with five treatments and four replications. Place and Duration of Study: The field experiment was conducted in a sandy soil area in Moncok Karya, Pejeruk Karya Village, Ampenan District, Mataram City. The analysis part was carried out in Microbiology laboratory, and in the Soil Physics and Chemistry Laboratory, Faculty of Agriculture, University of Mataram. All series of trials were completed in six months. Methodology: The experimental tested five treatments, namely; Control, no ameliorant (A0), Rice Husk Charcoal (AA), Cow Manure (AS), Compost (AK), and Fertile Organic Fertilizer (AP). Each treatment was replicated 4 times. Observations were made on biomass weight, crop yield, nutrient concentrations (N and P), nutrient uptake, and mycorrhizal activity. Results: Ameliorant treatment with cow manure significantly improved plant growth and productivity by enhancing nutrient availability in the soil. This included increases in biomass, and yield. Cow manure also promoted mycorrhizal activity, improved soil structure and increased nutrient absorption efficiency. Conclusion: The research result showed that the cow manure as an ameliorant markedly enhanced NP uptake and productivity of sweet corn in sandy soil. It improved soil fertility, supported mycorrhizal colonization, and strengthened plant resistance to environmental stresses.

Microalgae have emerged as a promising feedstock for carbon capture technology due to their high carbon sequestration efficiency and potential applications in bioenergy and bioproducts. This study aims to assess the prospects and implementation of microalgae-based carbon capture and storage (CCS) systems in mitigating climate change. The research involves a comprehensive review of microalgae cultivation methods, carbon capture efficiency, and conversion technologies such as biochar production, biofuel synthesis, and direct carbon sequestration in industrial applications. A systematic literature analysis was conducted to evaluate the effectiveness, scalability, and economic feasibility of microalgae-based solutions in mitigating climate change. The study also evaluates key factors influencing the scalability of microalgae-based systems, including biomass productivity, nutrient requirements, and technological advancements in harvesting and processing. Results indicate that microalgae exhibit high CO₂ absorption capacity and can be integrated into existing carbon capture frameworks with minimal land and resource constraints. Additionally, advancements in biorefinery approaches have enhanced the economic feasibility of microalgae-based negative carbon technologies. However, challenges such as high operational costs, energy-intensive processing, and regulatory barriers remain critical factors affecting large-scale adoption. In conclusion, microalgae offer a viable solution for negative carbon technologies, but their successful implementation requires interdisciplinary collaboration, technological improvements, and supportive policies to enhance efficiency and cost-effectiveness

Vermicomposting provides a green alternative to composting, which can reduce greenhouse gas emissions and improve soil health. As a result of existing waste management practices, greenhouse gases are released into the environment. Still, vermicomposting offers a sustainable solution by recycling organic waste into a soil amendment that improves soil health and increases crop yields. This study provides an in-depth overview of the benefits of vermicomposting, a practice that recycles organic waste materials into a nutrient-rich soil amendment called vermicompost, which can reduce greenhouse gas emissions, improve soil fertility, and boost crop yields by enhancing soil structure and microbial activity, thereby presenting vermicomposting as a sustainable way to recycle organic waste, while mitigating climate change, protecting soils, and boosting agriculture. This overview examines how vermicomposting organic waste lowers greenhouse gas emissions from landfills, improves crop yields through improved soil structure and fertility, and enriches soils by increasing microbial biodiversity and nutrient availability. Vermicomposting provides degradation and detoxification of organic waste with some nutrient-rich castings. The potential of these castings to improve soil health sparked interest among agricultural researchers. Crops fertilized with vermicompost thrived, producing higher yields and the nutrient density of the plants increased significantly. Emerging research reveals that vermicompost can fight against climate change. As an organic fertilizer, it enhances the ability of plants and soil to sequester carbon, decreasing greenhouse gases and also reducing emissions of methane and nitrous oxide compared to conventional fertilizers. With broader implementation, vermicomposting offers a meaningful path to combat climate change through regenerative agriculture.

This chapter reviews state-of-the-art biological processes and technologies for carbon capture and sequestration (CCS), including the major biological processes, approaches, and alternatives. The chapter discusses principles and related mechanisms for biological CCS at the ecosystem, organism, and molecular levels. It explains two major biological processes for carbon capture: the use of biomass/residuals for biomass energy generation with CO2 capture and the photosynthetic systems of microorganisms. Biotic sequestration is based on managed intervention of higher plants and microorganisms in removing CO2 from the atmosphere. Several environmental and economic advantages exist in using microalgae in biotic CCS from point sources. Reduced use of petroleum-derived fuels by the advanced use of biofuels can balance the release and fixation of carbon in the environment.

This abstract investigates the profound interconnection between carbon sequestration methods and soil health enhancement, crucial for sustainable land management. Evaluating various strategies, including cover cropping, reduced tillage, agroforestry, and biochar application, this study elucidates their role in augmenting soil organic carbon levels and fostering microbial diversity, thereby improving soil structure, water retention, nutrient cycling, and overall fertility. It examines the reciprocal impacts of carbon sequestration and soil health on agricultural yields, ecosystem resilience, and climate change mitigation. Furthermore, the research outlines barriers to widespread adoption, such as economic constraints and policy frameworks, emphasizing the need for interdisciplinary approaches and technological innovations. Overall, this study advocates integrating carbon sequestration practices into agricultural techniques as a pivotal step towards mitigating climate change and fortifying soil health for sustainable land use and resilient ecosystems.

Organic solid waste management is a significant challenge given environmental and sustainability concerns. Organic waste, including food residues, plant materials, agricultural waste, and other biological components, makes up a large portion of human-generated waste. Effective management of this waste is a priority for governments and businesses to reduce its ecological footprint and exploit its potential. Composting organic waste is an essential practice with numerous benefits for agriculture and the environment, turning waste into nutrient-rich compost that improves soil structure and health, reduces waste, decreases greenhouse gas emissions, and promotes sustainable agriculture.Olive pomace, the residue from olive oil extraction, is rich in fibers, residual oil, and polyphenols. When composted with other organic materials, it produces compost that enhances soil structure, water retention, and provides essential nutrients to plants. Household organic waste, such as food scraps and fruit and vegetable peelings, decomposes into compost rich in organic matter and nutrients, improving soil quality and structure. Poultry manure, high in nitrogen, phosphorus, and potassium, stabilizes nutrients and reduces pathogens when composted, producing balanced, nutrient-rich compost that enhances soil fertility and promotes healthy crop growth. Green waste, such as leaves and grass clippings, also benefits from composting, producing compost rich in organic matter that improves soil structure, increases water retention, and supplies essential nutrients to plants.Composting organic waste reduces waste, enriches soils, and supports sustainable agriculture by transforming olive pomace, household waste, poultry manure, and green waste into valuable compost. This practice reduces dependence on chemical fertilizers, contributing to sustainable farming and reducing water pollution caused by nutrient runoff. Organic waste valorization through composting is crucial in the circular economy, turning waste into valuable resources, reducing raw material needs, lowering waste management costs, and promoting sustainability. Studies have demonstrated the effectiveness of composts as soil amendments, reducing waste volume and management costs.