34,94 €
Mehr erfahren.
- Herausgeber: Bentham Science Publishers
- Kategorie: Lebensstil
- Sprache: Englisch
Biochar - Solid Carbon for Sustainable Agriculture explores the potential of biochar, a form of charcoal produced from organic materials, to improve soil health, increase crop yields, and mitigate climate change. This book offers a comprehensive overview of biochar and its applications in sustainable agriculture.
The book begins by introducing the concept of biochar and its historical use in agriculture. Next, the content deals with the production methods and properties of biochar, providing insights into its chemical composition and physical characteristics. Subsequent chapters explore the diverse applications of biochar in agriculture, including its role in soil fertility improvement, carbon sequestration, and pollution remediation. Case studies and practical examples illustrate the effectiveness of biochar across different agricultural settings. The authors also discuss the potential challenges and future directions of biochar research and application.
This book is essential reading for agronomists, soil scientists, environmental scientists, farmers, policymakers, and anyone interested in sustainable agriculture and climate change mitigation strategies.
Readership
Agronomists, soil scientists, environmental scientists, farmers, policymakers, and anyone interested in sustainable agriculture and climate change initiatives.
Das E-Book können Sie in Legimi-Apps oder einer beliebigen App lesen, die das folgende Format unterstützen:
Seitenzahl: 297
Veröffentlichungsjahr: 2024
Ähnliche
BENTHAM SCIENCE PUBLISHERS LTD.
End User License Agreement (for non-institutional, personal use)
This is an agreement between you and Bentham Science Publishers Ltd. Please read this License Agreement carefully before using the book/echapter/ejournal (“Work”). Your use of the Work constitutes your agreement to the terms and conditions set forth in this License Agreement. If you do not agree to these terms and conditions then you should not use the Work.
Bentham Science Publishers agrees to grant you a non-exclusive, non-transferable limited license to use the Work subject to and in accordance with the following terms and conditions. This License Agreement is for non-library, personal use only. For a library / institutional / multi user license in respect of the Work, please contact: [email protected].
Usage Rules:
All rights reserved: The Work is the subject of copyright and Bentham Science Publishers either owns the Work (and the copyright in it) or is licensed to distribute the Work. You shall not copy, reproduce, modify, remove, delete, augment, add to, publish, transmit, sell, resell, create derivative works from, or in any way exploit the Work or make the Work available for others to do any of the same, in any form or by any means, in whole or in part, in each case without the prior written permission of Bentham Science Publishers, unless stated otherwise in this License Agreement.You may download a copy of the Work on one occasion to one personal computer (including tablet, laptop, desktop, or other such devices). You may make one back-up copy of the Work to avoid losing it.The unauthorised use or distribution of copyrighted or other proprietary content is illegal and could subject you to liability for substantial money damages. You will be liable for any damage resulting from your misuse of the Work or any violation of this License Agreement, including any infringement by you of copyrights or proprietary rights.Disclaimer:
Bentham Science Publishers does not guarantee that the information in the Work is error-free, or warrant that it will meet your requirements or that access to the Work will be uninterrupted or error-free. The Work is provided "as is" without warranty of any kind, either express or implied or statutory, including, without limitation, implied warranties of merchantability and fitness for a particular purpose. The entire risk as to the results and performance of the Work is assumed by you. No responsibility is assumed by Bentham Science Publishers, its staff, editors and/or authors for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products instruction, advertisements or ideas contained in the Work.
Limitation of Liability:
In no event will Bentham Science Publishers, its staff, editors and/or authors, be liable for any damages, including, without limitation, special, incidental and/or consequential damages and/or damages for lost data and/or profits arising out of (whether directly or indirectly) the use or inability to use the Work. The entire liability of Bentham Science Publishers shall be limited to the amount actually paid by you for the Work.
General:
Any dispute or claim arising out of or in connection with this License Agreement or the Work (including non-contractual disputes or claims) will be governed by and construed in accordance with the laws of Singapore. Each party agrees that the courts of the state of Singapore shall have exclusive jurisdiction to settle any dispute or claim arising out of or in connection with this License Agreement or the Work (including non-contractual disputes or claims).Your rights under this License Agreement will automatically terminate without notice and without the need for a court order if at any point you breach any terms of this License Agreement. In no event will any delay or failure by Bentham Science Publishers in enforcing your compliance with this License Agreement constitute a waiver of any of its rights.You acknowledge that you have read this License Agreement, and agree to be bound by its terms and conditions. To the extent that any other terms and conditions presented on any website of Bentham Science Publishers conflict with, or are inconsistent with, the terms and conditions set out in this License Agreement, you acknowledge that the terms and conditions set out in this License Agreement shall prevail.Bentham Science Publishers Pte. Ltd. 80 Robinson Road #02-00 Singapore 068898 Singapore Email: [email protected]
PREFACE
In the ever-evolving landscape of agriculture and environmental sustainability, biochar stands as a remarkable, yet often underestimated, ally. As our world grapples with the challenges of feeding a growing population, mitigating the impacts of climate change, and restoring ecosystems tainted by contaminants, the role of biochar has emerged as a beacon of hope. This reference book, “Biochar: Solid Carbon for Sustainable Agriculture,” aims to shed light on the profound significance of biochar in addressing these multifaceted concerns.
Biochar, a carbon-rich substance formed through the pyrolysis of organic materials, possesses the unique ability to transform how we interact with our environment. Its origins can be traced back through centuries of trial and error, as humans sought to enhance soil fertility and reduce waste. Today, we have embarked on a journey to unlock the full potential of biochar in the context of contemporary agricultural practices and environmental management.
This book is the culmination of efforts from a diverse group of writers who share an interdisciplinary understanding of biochar. We have endeavored to create a platform where knowledge, research, and experience converge to offer a holistic exploration of biochar's applications and limitations. Our collective goal is to provide readers with a comprehensive guide that not only illuminates the art and science of biochar production but also delves into the intricate web of its effects on soil, agriculture, ecosystems, and the global environment.
Within these pages, you will find an in-depth exploration of the physical, chemical, and biological properties of biochar, as well as its role in the sequestration of heavy metals and greenhouse gases. We investigate how biochar influences soil organisms, from microorganisms to macroorganisms, and the consequent changes in enzyme activities. The book also addresses the tangible benefits of biochar in boosting agricultural productivity, enhancing crop yields, and controlling plant pathogens while simultaneously addressing its potential limitations and challenges.
The journey you are about to embark on is one of discovery, innovation, and a shared commi-tment to a more sustainable world. It is our hope that “Biochar: Solid Carbon for Sustainable Agriculture” serves as both a reference point and an inspiration for working teams worldwide as they seek to determine outcomes and pinpoint future research needs. Together, we can harness the power of solid carbon in the form of biochar to cultivate a more resilient, productive, and harmonious relationship with our planet.
ENDORSEMENT
In "Biochar - Solid Carbon for Sustainable Agriculture," editors Rubab Sarfraz and Christopher Rensing have compiled a groundbreaking exploration into one of the most promising solutions for our agricultural and environmental challenges. This meticulously researched and thoughtfully crafted book not only sheds light on the transformative potential of biochar but also serves as a roadmap for its widespread adoption.
Biochar, with its ability to improve soil fertility, sequester carbon, and mitigate climate change, represents a beacon of hope in our quest for sustainable agriculture. Through a blend of scientific expertise and practical insights, Sarfraz and co- have curated a collection of chapters that offer a comprehensive understanding of biochar's applications—from its production and properties to its impact on crop productivity and ecosystem health as well as covering the cost dynamics.
What sets this book apart is its accessibility and relevance. Whether you're a seasoned researcher, a farmer looking to enhance soil health, or a policymaker seeking innovative solutions, "Biochar - Solid Carbon for Sustainable Agriculture" provides invaluable insights that can inform decision-making and drive meaningful change. Moreover, by addressing not only the technical aspects but also the socioeconomic and policy dimensions of biochar adoption, this book fosters a holistic perspective that is essential for effective implementation.
As we confront the urgent challenges of climate change and food security, "Biochar - Solid Carbon for Sustainable Agriculture" emerges as a timely and indispensable resource. Editor and authors have done a great job to bring together a diverse array of perspectives, making this book a must-read for anyone passionate about building a more sustainable future.
List of Contributors
The Science of Biochar Production: Understanding the Formation and Characteristics of Biochar
Rubab Sarfraz1,Muhammad Tayyab2,*,Awais Shakoor3,Muhammad Waqas Khan Tarin4,Iqra Sahar5Abstract
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.
INTRODUCTION
Since the green revolution, greater use of agrochemical-based crop production methods, as well as rapid industrialization, has raised crop yields while maintaining nutritional levels; however, excessive use of mineral fertilizers has resulted in rapid decomposition of organic matter, stimulating the microbial activity ultimately leading to the quicker breakdown of organic matter. As a consequence, this accelerated decomposition can influence the overall dynamics of soil organic carbon and nutrient cycling [1-3]. Extensive research has been conducted to restore degraded agricultural soils and natural resources to address these issues [4, 5]. Organic residues, such as compost, manure, and other organic materials, have been shown to be a viable alternative to mineral fertilization [6, 7]. However, because of their low nutritional content and rapid degradation rate, these materials must be used in large amounts.
Biochar's application in environmental management has gained significant attention in recent years due to its numerous benefits. Biochar is a porous, fine-grained material that is employed in the soil to increase its fertility. It is produced in a sustainable manner as a byproduct of biomass bioenergy. Biochar has important environmental and agricultural implications due to its versatility and heterogeneity. Its physicochemical properties, such as high adsorption potential, buffering, cation exchange capacity and specific surface area are critical in evaluating the scope and direction of the responses triggered by its application.
Furthermore, the type of biomass and biochar production underlying pyrolysis conditions have a significant impact on its physicochemical and structural properties, such as functional groups, surface area, polarity and pH, which eventually define its overall surface properties [8, 9]. These changes in biochar characteristics have a major impact on its efficiency in improving soil fertility, nutritional status, and agricultural productivity. Biochar application recovers the soil's chemical, physical, and biological properties [5], and actions as a soil conditioner, cumulative soil water holding capacity and nutrient levels, resulting in not only improved seed germination but also crop growth and production [10, 11]. These biochar properties also increase the soil microbial population, which contributes to overall positive effects on soil health [12].
Origin of Biochar
The production of biochar, also known as Terra Preta, is an ancient practice that dates back to Egyptian societies over 70 centuries ago. While the primary purpose of biochar production in ancient Egypt was not solely for agricultural use, the liquid wood tars produced through charring processes were used to embalm the bodies of the dead (Emrich, 1985). The term “black earth of the Indios” is commonly used to refer to a specific type of soil that has attracted the scientific community’s consideration across the world. It is thought that Terra Preta is the outcome of indigenous cultures modifying the soil through activities such as cooking and agriculture [13].
The Terra Preta discovery occurred in the Brazilian Amazon, where large amounts of pottery and human-made objects were found in areas with soil that greatly differed from the surrounding land despite similar mineralogy and texture [14]. Unlike the typical, unproductive soils of the Amazon rainforest, Terra Preta is characterized by its black color, alkaline pH, and rich microorganisms [15]. Terra Preta soils have higher total carbon storage, approximately 250 t C ha-1 m-1, than the typical value (100 t C ha-1 m-1) in adjacent soils [16, 17].
This soil is represented by a high charcoal content, more than 70 times that of the surrounding soil, and can be found at a depth of 40-80 cm. Over thousands of years, it is believed to be the result of the local people's use of the “slash and char strategy”, introducing plant remains into the soil through incomplete combustion [14]. Terra Preta's carbonaceous fraction is chemically and microbiologically stable due to its complicated aromatic polycyclic chemistry, which might remain in the environment for decades. As it oxidizes on the surface, it produces carboxylic groups, increasing its capacity to retain nutrients.
This “black fortune” that defines a substantial portion of the Amazon basin and other South American regions is thought to be ascribed to the Pre-Columbian civilization that inhabited the Amazon between 2500 and 500 BC. West Africa and Borneo were additionally characterized as having equivalent soils [18].
Production and Formation of Biochar
Biochar is a substance made up of components like hydrogen, carbon, sulfur, nitrogen, and oxygen, as well as minerals in the ash fraction [19]. It is formed during pyrolysis, which is the thermal decomposition of biomass in a low-oxygen environment. It is highly porous, black, fine-grained, with a high surface area, light weight, and high pH, all of which contribute to its soil application effect [20]. For improving soil quality and increasing crop productivity while mitigating pollution, biochar is applied to the soil, and its properties depend on the biomass used for its production as well as processing parameters.
Biomass for Biochar Generation
Biochar manufacturing is now recognized as one of the most environmentally friendly approaches in tackling soil fertility issues, with an immense quantity of biological waste being used to produce biochar [5, 21, 22]. The utilization of biological waste for the production of biochar is a highly sustainable approach to address issues of soil fertility. With the increasing population, there is an increase in food production, resulting in the generation of significant amounts of organic residues. Therefore, recycling these residues is crucial. A wide range of biomass feedstocks can be used for biochar production, such as forestry, agricultural by-products (e.g., straw, wood chips, rice hulls, nut shells, wood pellets, tree bark, and switch grass) and industrial by-products (e.g., paper sludge, sugar cane bagasse and pulp, mushroom residues, and animal wastes, including dairy, chicken litter, sewage sludge and swine manure). Utilizing biomass, particularly waste, to produce biochar is an effective way of recycling these materials. Pyrolysis treatment decreases the volume and weight of biomasses [5, 19, 21-23].
Biochar Production Methods
Biochar can be produced through various methods, and the process of its production involves the thermal decomposition of biomass feedstock in a lower oxygen environment, resulting in the generation of biochar along with oil and gases as by-products (Fig. 1) [24]. The feedstock, which is typically dry waste cut into small pieces of less than 3 cm, is heated at temperatures ranging from 350-700°C (662-1292°F) in the absence or presence of minimal oxygen. Pyrolysis can be further classified based on the temperature and duration of heating, such as fast pyrolysis, slow pyrolysis, and gasification.
Fast Pyrolysis
High-temperature pyrolysis, typically occurring at temperatures above 500°C and with rapid heating rates, results in the maximum production of bio-oil. In contrast, low-temperature pyrolysis, taking place at temperatures between 250-500°C and with slower heating rates, produces more biochar over a longer period of time [25].
Slow Pyrolysis
During slow pyrolysis, the feedstock is heated at a slower rate (heating rates ≤ 100°C/min) and for a longer duration, ranging from 30 minutes to a few hours, to fully decompose the organic material. This process results in the production of a greater amount of biochar compared to fast pyrolysis. The optimal temperature range for slow pyrolysis is between 250-500°C [25].
Gasification
Gasification takes place at temperatures higher than those used in fast and slow pyrolysis, typically between 600°C to 1800°C [26]. This process primarily aims to maximize the production of syngas and produces less biochar compared to fast and slow pyrolysis.
Factors Influencing Biochar Characteristics
Biochar attributes are greatly affected by the pyrolysis conditions and the type of feedstock used in its production [23]. Various factors (e.g., feedstock selection, pyrolysis temperature, pyrolysis time, and holding time) play key roles in defining the properties of biochar Table 1. Some of the specific ways in which these factors affect the properties of biochar are discussed below:
Biochar Physicochemical Properties
The amount produced of biochar reduces as the pyrolysis temperature rises, owing mainly to the polymerization of compounds such as hemicellulose and cellulose, as well as the combustion of organic products. The main cause of the reduction in yield is a rise in the degree of volatilization of organic compounds with rising temperatures. The higher biochar production at low temperatures suggest that the material undergoes only partial pyrolysis [27]. At low temperatures, the heating rate has a greater impact on biochar yield, while at high temperatures, the trend is similar [28]. A study reported that biochar yields changed (4.48% change) at 400°C as the heating rate augmented from 10 to 50°C min-1; but, at 600°C, the biochar productivity changed only 1.76% under a slight increase in heating rate [28].
Temperature and heating rate have a significant impact on the chemical properties of biochar. For instance, with a rise in temperature, the pH values of the biochar also enhance [28]. The influence of pyrolysis temperature on pH is primarily due to two factors:
A rise in the number of basic cations in the ashes, which can be linked to alkaline species, including oxides, carbonates, and hydroxides [29], andA decrease in the level of acidic surface functional groups [30].Biochar's cation exchange capacity (CEC) normally declines as the pyrolysis temperature is increased, which in part, is due to the depletion of carboxylic biochar surface functional groups [31]. The carbon content of biochar increases due to rising pyrolysis temperature, but the oxygen and hydrogen concentration decreases relative to the carbon content [32]. The loss of oxygen and hydrogen content may be responsible for the shattering of weak bonds within the biochar structure.Furthermore, the aromatic C structures coupled with acidic functional groups can influence biochar CEC and adsorption capability [33]. The reduction in cation exchange capacity (CEC) of biochar with increasing pyrolysis temperature can be ascribed to the degradation of acid functional groups and volatile organic compounds [34]. These functional groups have been linked to the negative surface charge of biochar [33]. At a pyrolysis temperature of 400°C, the number of micropores significantly increases as volatile matter is removed, resulting in a rise in surface area and pore volume. However, at high temperatures, structural changes, merging of adjacent pores and pore enlargement often dominate, leading to a decrease in surface area. In addition, pores in biochar may shrink due to extrusion, fusion, softening, and carbonization [35].
Biochar Macronutrients Contents
The properties of biochar may vary depending on the temperature at which it is produced. High-temperature pyrolysis (>550°C) results in biochar with high surface areas (> 400m2 g-1) [36, 37], high levels of aromatic compounds that make it resistant to decomposition, and good adsorbent properties [38, 39]. On the other hand, low-temperature pyrolysis (< 550°C) leads to a larger recovery of carbon and nutrients (e.g., sulfur and such as nitrogen) that are lost at higher temperatures [37]. Biochars produced at lower temperatures have a less condensed C structure and are likely to be more reactive in soils than those produced at higher temperatures [40].
Most biochars contain very little nitrogen (N) because N volatizes at temperatures above 200 and 375ºC. However, biochars produced from feedstocks with high N content may contain more N [23]. Recent studies have also shown that the feedstock and pyrolysis temperature can affect soil phosphorus (P) availability. For instance, biochar produced from digestate solids at low temperatures had a slight impact on P speciation; however, P became more thermodynamically stable in species such as apatite as the temperature increased above 600˚ C. Very high temperatures above 1000 ˚C indicated reduced forms of P [41]. Additionally, animal-derived biochar has been found to supply more P for plant growth than plant-derived biochar [42].
Biochar Heavy Metal Contents
Some biochars may contain heavy metals, mineral dioxins, contaminants, and polycyclic aromatic hydrocarbons (PAHs). Biochar with these heavy metals is often due to pyrolysis conditions or contaminated feedstock use that favors their production. For instance, pyrolysis at temperatures below 500 °C can lead to an accumulation of sulfur (S) in biochar [43]. Similarly, PAHs, heavy metals, and toxic antibiotics may also accumulate under these conditions. Biochars produced from organic waste such as sewage sludges, biosolids, and tannery wastes may contain high concentrations of heavy metals [44]. High concentrations of nickel (Ni), zinc (Zn), copper (Cu), and chromium (Cr) have been found in biochars produced from sewage sludge.
In contrast, biochars produced from pine chip, peanut hull, and poultry litter at temperatures between 400 to 500°C were found to have relatively low concentrations of molybdenum (Mo), chromium (Cr), aluminum (Al), and nickel (Ni) [45]. Similarly, at higher pyrolysis temperatures, such as 700 °C, the highest concentrations of magnesium (Mg), iron (Fe), manganese (Mn), and calcium (Ca) were recorded in the waste mushroom substrate; due to these elements, the concentration increases with temperature [23, 46]. Careful and comprehensive risk assessments for these contaminants are essential to determine the toxicity of different biochar types, safe application rates, and appropriate pyrolysis conditions.
Production of Biochar with the Intention of Agronomic and Environmental Benefits
Biochar produced from diverse pyrolysis temperatures and biomass sources can have varying effects on soil acidity, nutrient availability, crop yield, and global climate change [16, 17, 21]. Biochar produced at high temperatures has a higher pH, indicating the presence of alkaline chemical species, which may decrease the availability of Mn and Fe and increase soil CEC [47]. This can lead to a decrease in precipitation and adsorption of P [48] and an increase in the supply of K and Ca for plants. Additionally, P availability in biochar patches was firstly lower than that in manure solids, but increased over time, while biochar produced at higher temperatures had very lower extractable P. These findings suggest that biochar produced at lower temperatures may have higher immediate P availability, but the long-term effects of biochar produced at higher temperatures on P availability are still uncertain [49] Table 1.
The C and N cycles in soil are greatly affected by the pyrolysis temperature of biochar. To reduce CO2 emissions, it is recommended to use low labile C biomass that is pyrolyzed at temperatures above 550˚C [50]. The volatile matter content in biochar is also important for evaluating C and N cycling in soil ecosystems. High aliphatic character (high O/C ratios) observed at low temperatures (350 and 450˚C) can indicate that biochar is susceptible to degradation by soil microorganisms, which can cause short-term immobilization of inorganic N in soil [50]. This can hinder the supply of N to plants, but it can also be beneficial for reducing N2O emissions and inorganic-N leaching from soils.
The labile C fraction in biochar can easily decompose and, in some cases, can stimulate the mineralization of native soil organic matter through a positive priming effect. This is more likely to occur in soils treated with biochar produced at low temperatures, but this is not always the case. Low-temperature biochar (350 and 450˚C) can be considered an index of biochar susceptibility to degradation by soil microorganisms, causing short-term immobilization of inorganic N in soil, and this N immobilization may hamper the supply of N to plants in biochar-treated soils.
Low-temperature biochars (300-400°C) have the largest CEC, which can make them effective in adsorbing N-NH4+ up to 2.3 mg g-1 and reducing N leaching rates [51]. High-surface-area biochars generated at high temperatures (>600˚C) usually have low CEC, but the aging effect may come into play, oxidizing the organic biochar, increasing the negative charge density and increasing the formation of biochar-mineral complexes [52].
Overall, researchers have found that biochar created at higher pyrolysis temperatures caused a greater reduction in cumulative CO2 release compared with biochar produced at lower temperatures [50]. However, more research is needed to fully understand the effects of different pyrolysis temperatures and biomass sources on biochar's potential to improve soil acidity, nutrient availability, crop yield, and global climate change.
Future Perspective
The properties of biochar play a significant role in determining its applications, making it essential for future researchers to understand how the production process affects these properties. Different types of biochar may be required for different purposes, such as water treatment or energy and agriculture. Additionally, the effects of biochar on agriculture, specifically on crop production, can vary depending on the soil type and fertilizer management. Studies have shown that crop yields can be affected differently by biochar depending on the soil type and fertilization practices [5, 53, 54]. Additionally, the chemical behavior of biochar with heavy metal ions has been found to be inconsistent [55]. It is clear that the interactions between biochar, soil, and plants are complex and not fully understood. Therefore, more research is needed to better understand the properties of biochar and its effects on soil and crop response, both in the field and in controlled environments.
