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Soil biochar is a kind of organic matter rich in carbon, which is of great significance in soil fertility improvement, fertilizer type innovation and greenhouse gas emission reduction. In this paper, Mg-modified biochar was prepared by thermal cracking using rice straw and corn straw as raw materials. The Mg-modified biochar and unmodified biochar were fully mixed with prepared soil samples at the addition amounts of 0.5% (w/w), 1% (w/w) and 2% (w/w), respectively, and then simulated indoor soil cultivation experiments were carried out. The effects of magnesium ion-modified biochar and non-modified biochar on soil chemical properties and the effects of different amounts of biochar on soil properties were studied. The results showed that the yield of Mg-modified biochar from rice straw and corn straw, prepared by pyrolysis, was 65%, and the ash content was large. The pH of MG-modified corn stalk biochar (MCBC) is weakly basic (8.55), while the pH of MG-modified rice stalk biochar (MRBC) is basic (10.1), and their internal structures are slightly different. After the application of biochar prepared from rice straw and maize stover, soil indicators were determined. Compared to the control, the chemical properties of the treated soil samples were significantly improved, with an increase in soil pH, an increase in the content of effective nutrients, such as fast-acting potassium, fast-acting phosphorus and alkaline dissolved nitrogen, and an increase in the content of the total phosphorus and total nitrogen, as well as an increase in the content of organic matter. The Mg-modified biochar was generally superior to the unmodified biochar in improving soil fertility, at the same addition level. It was also found that the rice-straw biochar performed better than the corn-stover biochar and had a more obvious effect on soil improvement in terms of fast-acting potassium, ammonium nitrogen, nitrate nitrogen, total phosphorus and total nitrogen contents. [ABSTRACT FROM AUTHOR]

The growing energy consumption and the need for a circular economy have driven considerable interest in the anaerobic digestion (AD) of organic waste, offering potential solutions through biogas and digestate production. AD processes not only have the capability to reduce greenhouse gas emissions but also contribute to the production of renewable methane. This comprehensive review aims to consolidate prior research on AD involving different feedstocks. The principles of AD are explored and discussed, including both chemical and biological pathways and the microorganisms involved at each stage. Additionally, key variables influencing system performance, such as temperature, pH, and C/N ratio are also discussed. Various pretreatment strategies applied to enhance biogas generation from organic waste in AD are also reviewed. Furthermore, this review examines the conversion of generated digestate into biochar through pyrolysis and its utilization to improve AD performance. The addition of biochar has demonstrated its efficacy in enhancing metabolic processes, microorganisms (activity and community), and buffering capacity, facilitating Direct Interspecies Electron Transfer (DIET), and boosting CH4 production. Biochar also exhibits the ability to capture undesirable components, including CO2, H2S, NH3, and siloxanes. The integration of digestate-derived biochar into the circular economy framework emerges as a vital role in closing the material flow loop. Additionally, the review discusses the environmental benefits derived from coupling AD with pyrolysis processes, drawing on life cycle assessment investigations. Techno-economic assessment (TEA) studies of the integrated processes are also discussed, with an acknowledgment of the need for further TEA to validate the viability of integrating the biochar industry. Furthermore, this survey examines the techno-economic and environmental impacts of biochar production itself and its potential application in AD for biogas generation, aiming to establish a more cost-effective and sustainable integrated system. [ABSTRACT FROM AUTHOR]

This article explores the potential benefits of using zinc lysine and biochar to enhance the growth and physiological performance of wheat plants under saline stress. The study found that the combined application of biochar and zinc lysine significantly improved various physiological attributes and reduced oxidative stress indicators. The authors suggest that this combined treatment could be a practical solution to mitigate salt stress in plants, but further field studies are needed to validate these findings. The document also includes a list of references that library patrons can use to further explore topics related to plant stress and agricultural practices. [Extracted from the article]

Biochar, a carbon-rich material produced from biomass waste through thermal conversion, holds great environmental promise. This article offers a comprehensive overview of the various feedstocks used in biochar production, the different types of thermal degradation processes, biochar characterization, properties, modifications to engineered materials, and their applications in the environment. The quality of biochar, including surface area, pore size and volume, and functional group formation, is significantly influenced by the specific conditions under which thermal conversion takes place. Each of the diverse processes employed to produce biochar yields a distinct set of properties in the final product. In recent years, biochar has gained widespread recognition and utilization in diverse fields such as wastewater treatment, carbon sequestration, reduction of greenhouse gas emissions, biogas production, catalysis in biofuel industries, construction, and soil enhancement. In summary, biochar is a promising environmental mitigation tool to achieve a sustainable environment. In addition to its benefits, the application of biochar presents several challenges, including the selection of feedstocks, methods of biochar production, modifications to biochar, the properties of biochar, and the specific applications of biochar. The current review summarizes factors that could lead to significant advancements in future applications. Highlights: The feedstocks and production of biochar were discussed. Activation of biochar and properties of biochar were narrated and summarized. Application of biochar for sustainable environment was discussed. [ABSTRACT FROM AUTHOR]

Biochar, with its potential to enhance soil fertility, sequester carbon, boost crop yields and reduce greenhouse gas emissions, offers a solution. Addressing the challenges posed by climate change is crucial for food security and agriculture. However, its widespread adoption in agriculture remains in its infancy. This study assessed the effects of rice hull biochar on cabbage production and greenhouse gas emissions, especially nitrous oxide (N2O). A trial, employing a randomized block design in triplicate was conducted from September 13 to November 23, 2022, where "Cheongomabi" cabbage was cultivated with N-P2O5-K2O fertilization at 32 - 7.8 - 19.8 kg 10a−1. Additional fertilizer was applied twice post-sowing. The Biochar application rates were control = 0 ton ha−1, B1 = 1 ton ha−1, B3 = 3 ton ha−1, and B5 = 5 ton ha−1. The aboveground biomass of autumn cabbage harvested 82 days after sowing was 2.40–2.70 kg plant−1 in the control and biochar treatments (B1, B3, and B5), with no significant differences (p > 0.05). Cumulative CO2 emissions during cultivation varied across treatment groups, with initial and cumulative emissions of 10.40–17.94 g m−2 day−1 and 3.63–4.43 ton ha−1, respectively. N2O emissions decreased with higher biochar application: reductions of 2.9%, 25.4%, and 41.1% in the B1, B3, and B5 treatments, respectively, compared to the control. The biochar application had no significant impact on yield but curbed soil emissions, Net ecosystem carbon balance during cabbage cultivation ranged from 0.42 to 3.41 ton ha−1 for the B1, B3, and B5 treatments, respectively, compared to control. Overall, the study underscores biochar's role in mitigating emissions and boosting soil carbon during cabbage cultivation in fall. [ABSTRACT FROM AUTHOR]

Environmental restoration and sustainable energy solutions require effective management and utilization of agricultural crop residues to reduce greenhouse gas emissions. Biowastes are a valuable resource that can be converted into biofuels and their byproducts, solving the energy crisis and reducing environmental impact. In this study, teff husk, primarily generated in Ethiopia during the production of teff within the agro-industrial sector, is used as a feedstock for slow pyrolysis. Ethiopia generates an estimated annual production of over 1.75 million tons of teff husk, a significant portion of which is incinerated, resulting in significant pollution of the environment. This study focuses on assessing teff husk as a potential material for slow pyrolysis, a crucial stage in biochar production, to tap into its biochar-producing potential. To identify the composition of biomass, the teff husk underwent an initial analysis using thermogravimetry. The significant presence of fixed carbon indicates that teff husk is a viable candidate for pyrolytic conversion into biochar particles. The process of slow pyrolysis took place at three temperatures—specifically, 400, 450, and 500 °C. The maximum biochar yield was achieved by optimizing slow pyrolysis parameters including reaction time, temperature, and heating rate. The optimized reaction time, temperature, and heating rate of 120 min, 400 °C, and 4.2 °C/min, respectively, resulted in the highest biochar yield of 43.4 wt.%. Furthermore, biochar's physicochemical, SEM-EDX, FTIR, and TGA characterization were performed. As the temperature of biochar increases, its carbon content and thermal stability increases as well. Unlike fuel recovery, the results suggest that teff-husk can be used as a feedstock for biochar production. [ABSTRACT FROM AUTHOR]

Biochar is a promising pyrolysed carbon-enriched soil amendment and has excellent properties for agriculture production and to remediate environmental pollution. A set of reviews were conducted on biochar production by pyrolysis process from various waste biomass which has drawn extensive interest due to the low cost of production with several benefits. As many potential technologies have been developed, there are still several knowledge gaps that have been identified for some key points to contribute a comprehensive study towards soil fertility, nutrient and water retention, soil microbial activity, plant growth and yield, pollution remediation, mitigation of greenhouse gas emission and an improvement in the farmer's economy to achieve maximum profit by adopting environmentally friendly technique "pyrolysis". Therefore, this review explored a detailed study on food waste biochar production by the pyrolysis process and its impact on different applications as an amendment. Slow pyrolysis process at low and medium temperatures is a potential amendment for agriculture production and soil and water remediation by enhancing biochar properties like carbon, BET surface area, cation exchange capacity, zeta potential, and nutrient content, etc. with minimum ash content. The biochar enhances soil water and nutrient retention capacity, crop yield, and improved microbial community at different soil quality. Additionally, food waste to biochar is a realistic adsorbent and economical carbon sequester to mitigate GHG emissions. This review conducted a brief assessment of the knowledge gaps and future research directions for researchers, encouraging investigators, stakeholders, and policymakers to make the best possible decision for food waste valorization. Highlights: • Valorization of food waste to biochar is a promising amendment for agriculture and soil–water remediation. • Lower and medium pyrolysis temperatures qualitatively changed all aspects of biochar properties. • Biochar improves soil fertility, microbial activity, soil water and nutrient retention capacity, and plants growth. • Biochar is a good carbon sequestrator to mitigate greenhouse gas and a bioeconomy product for the farmer's community and policymakers. [ABSTRACT FROM AUTHOR]

The state of Sonora, Mexico, stands as one of the leading producers of pecan nuts in the country, which are commercialized without shells, leaving behind this unused residue. Additionally, this region has abundant solar resources, as shown by its high levels of direct normal irradiance (DNI). This study contributes to research efforts aimed at achieving a synergy between concentrated solar energy technology and biomass pyrolysis processes, with the idea of using the advantages of organic waste to reduce greenhouse gas emissions and avoiding the combustion of conventional pyrolysis through the concentration of solar thermal energy. The objective of this study is to pioneer a new experimental analysis methodology in research on solar pyrolysis reactors. The two main features of this new methodology are, firstly, the comparison of temperature profiles during the heating of inert and reactive materials and, secondly, the analysis of heating rates. This facilitated a better interpretation of the observed phenomenon. The methodology encompasses two different thermal experiments: (A) the pyrolysis of pecan shells and (B) the heating–cooling process of the biochar produced in experiment (A). Additionally, an experiment involving the heating of volcanic stone is presented, which reveals the temperature profiles of an inert material and serves as a comparative reference with experiment (B). In this experimental study, 50 g of pecan shells were subjected to pyrolysis within a cylindrical stainless-steel reactor with a volume of 156 cm3, heated by concentrated radiation from a solar simulator. Three different heat fluxes were applied (234, 482, and 725 W), resulting in maximum reaction temperatures of 382, 498, and 674 °C, respectively. Pyrolysis gas analyses (H2, CO, CO2, and CH4) and characterization of the obtained biochar were conducted. The analysis of heating rates, both for biochar heating and biomass pyrolysis, facilitated the identification, differentiation, and interpretation of processes such as moisture evaporation, tar production endpoint, cellulosic material pyrolysis, and lignin degradation. This analysis proved to be a valuable tool as it revealed heating and cooling patterns that were not previously identified. The potential implications of this tool would be associated with improvements in the design and operation protocols of solar reactors. [ABSTRACT FROM AUTHOR]

Mining sector has been the central attention of the business and public policy sustainable development scheme for several years. Reclamation territories are with potential carbon sequestration capacity in degraded mining areas and can be an impeccable option for achieving sustainable development goal-13. This paper made an investigation about the presence of heavy metals in reclaimed area possibilities to improve reclaimed soils with biochar with idea to enhance ecosystem carbon pool and atmospheric CO2 sequestration capacity to offset CO2 emission and soil organic carbon losses. The results show that the carbon content in biochar is 46.6 % and would be classified in class 2 according to the International Biochar Initiative. H/C and O/C atomic ratios could be useful for restoration of degraded poor mine soils through enhanced carbon sequestration. O/C ratio is 0.085 mol mol–1 and half-life of biochar is 2795.65 years, which confirm the biochar stability. For each kilogram of biochar incorporated into the soil, 144 g of carbon were sequestrated 52,8 % CO2 emission reduction. Hence, the biochar developed in this study can be used in carbon-deficient soils with the added benefit of long-term carbon storage. [ABSTRACT FROM AUTHOR]

The creation of the carbon market came forth as a tool for managing, controlling, and reducing greenhouse gas emissions, combining environmental responsibility with financial incentives. Biochar has gained recognition as one of potential carbon offset solution. The practical and cost-effective establishment of biochar carbon credit standards is crucial for the integration of biochar into carbon trading systems, thus encouraging investments in the biochar industry while promoting sustainable carbon dioxide sequestration practices on a global scale. This communication focuses on the potential of biochar in carbon sequestration. Additionally, it spotlights case studies that highlight how biochar effectively generates carbon credits, as well as discussing the evolving carbon removal marketplace. Furthermore, we address knowledge gaps, areas of concern, and research priorities regarding biochar implementation in carbon credits, with the aim of enhancing our understanding of its role in climate change mitigation. This review positions biochar as a versatile and scalable technology with the potential to contribute significantly to carbon credits, aligning with sustainable development goals. It calls for continued research, transparency, and international cooperation to explore the full potential of biochar in climate change mitigation efforts. [ABSTRACT FROM AUTHOR]

Pyrolysis is a thermochemical technology for converting biomass into energy and chemical products consisting of bio-gas, bio-oil, and biochar. Several parameters influence the process efficiency and properties of pyrolysis products. These include the type of biomass, biomass preliminary preparation, gaseous atmosphere, final temperature, heating rate, and process time. This manuscript provides a general summary of the properties of the pyrolytic products of waste rapeseed cake, with particular emphasis on the sorption properties of biochar. Biochar, produced by the pyrolysis process of biomass, is emerging as a powerful tool for carbon sequestration, reducing greenhouse gas emissions, and purifying water from contaminants such as potentially toxic elements and antibiotics. The review found that the biochar obtained as a result of pyrolysis of chemically modified waste rapeseed cake is characterised by its excellent sorption properties. The obtained sorbents are characterised by sorption capacity relative to the copper(II) ion, ranging from 40 mg·g−1 to 100 mg·g−1, according to the pyrolysis conditions and chemical modification method. The purified pyrolysis gas obtained in the high-temperature process can be used to generate heat and energy. Bio-oil, with its significant combustion heat of 36 MJ·kg−1, can be a source of environmentally friendly green biofuel. [ABSTRACT FROM AUTHOR]

Manure is a leading source of methane (CH4), nitrous oxide (N2O), and ammonia (NH3) emissions, and alternative manure management practices can help society meet climate goals and mitigate air pollution. Recent studies show that biochar‐composting can substantially reduce emissions from manure. However, most studies test only one type of biochar applied at a single application rate, leading to high variation in emission reductions between studies. Here, we measured greenhouse gas and NH3 emissions during biochar‐composting of dairy manure with biochar applied at 5% or 20%, by mass, and made from walnut shells, almond shells, or almond clippings. We found little difference in emissions between biochar type. However, we found that the 20% application rates increased CH4 emissions and decreased N2O and NH3 emissions, resulting in a net reduction in global warming potential (GWP). We attribute this result to biochar increasing the formation of compost aggregates, which likely acted as anaerobic reactors for methanogenesis and complete denitrification. Biochar may have further fueled CH4 production and N2O consumption by acting as an electron shuttle within aggregates. We recommend lower application rates, as we found that the 5% treatments in our study led to a similar reduction in GWP without increasing CH4 emissions. [ABSTRACT FROM AUTHOR]

The global impact of water and soil contamination has become a serious issue that affects the world and all living beings. In this sense, multiple treatment alternatives have been developed at different scales to improve quality. Among them, biochar has become a suitable alternative for environmental remediation due to its high efficiency and low cost, and the raw material used for its production comes from residual biomass. A biochar is a carbonaceous material with interesting physicochemical properties (e.g., high surface area, porosity, and functional surface groups), which can be prepared by different synthesis methods using agricultural wastes (branches of banana rachis, cocoa shells, cane bagasse, among others) as feedstock. This state-of-the-art review is based on a general description of biochar for environmental remediation. Biochar's production, synthesis, and multiple uses have also been analyzed. In addition, this work shows some alternatives used to improve the biochar properties and thus its efficiency for several applications, like removing heavy metals, oil, dyes, and other toxic pollutants. Physical and chemical modifications, precursors, dopants, and promoting agents (e.g., Fe and N species) have been discussed. Finally, the primary uses of biochar and the corresponding mechanism to improve water and soil quality (via adsorption, heterogeneous photocatalysis, and advanced oxidation processes) have been described, both at laboratory and medium and large scales. Considering all the advantages, synthesis methods, and applications, biochar is a promising alternative with a high potential to mitigate environmental problems by improving water and soil quality, reducing greenhouse gas emissions, and promoting the circular economy through residual biomass, generating value-added products for several uses. [ABSTRACT FROM AUTHOR]

Improving soil management to enhance soil carbon sequestration (SCS)—a cost-efficient carbon dioxide (CO2) removal approach—can result in co-benefits or trade-offs. Here we address this issue by setting up a modeling framework for Switzerland that combines soil carbon (C) storage, food production and agricultural greenhouse gas (GHG) emissions. The link to food production is crucial because crop types and livestock numbers influence soil organic C (SOC) stocks, through soil C inputs from plants and manure. We estimated SCS rates for the years 2020–2050 for three scenarios, each with two variants for biochar: cover cropping (0.30 t CO2 equivalents [CO2-eq] ha−1 yr−1), biochar addition (0.36–1.8 t CO2-eq ha−1 yr−1) and agroforestry-biochar addition (2.2–2.3 t CO2-eq ha−1 yr−1). Different limiting factors (land and biomass availability, population growth) affected SCS rates and indicated that they cannot be sustained until 2100 under all scenarios (cover cropping: 0.10 t CO2-eq ha−1 yr−1 [2051–2100]; biochar addition: 0.35–1.8 t CO2-eq ha−1 yr−1; agroforestry-biochar addition: 1.0–1.7 t CO2-eq ha−1 yr−1). This information together with the associated GHG emissions is critical for planning net zero strategies and highlights the importance of integrated assessments that capture links between SCS and the food system. [ABSTRACT FROM AUTHOR]

Biochar has gained significant attention in agricultural and environmental research over the last two decades. This comprehensive review evaluates the effects of biochar on soil organic carbon (SOC), emission of non-CO2 greenhouse gases, and crop yield, including related mechanisms and major influencing factors. The impacts of biochar on SOC, methane and nitrous oxide emissions, and crop yield are controlled by biochar and soil properties and management practices. High-temperature biochar produced from lignin-rich feedstocks may decrease methane and nitrous oxide emissions in acidic soils and strengthen long-term carbon sequestration due to its stable aromatic structure. In contrast, low-temperature biochar from manure may increase crop yield in low-fertility soils. Applying biochar to farmlands in China can increase SOC content by 1.9 Pg C and reduce methane and nitrous oxide emissions by 25 and 20 Mt CO2-eq year−1, respectively, while increasing crop yields by 19%. Despite the increasing evidence of the positive effects of biochar, future research needs to explore the potential factors that could weaken or hinder its capacity to address climate change and secure crop production. We conclude that biochar is not a universal solution for global cropland; however, targeted applications in fields, landscapes, or regional scales, especially in low fertility and sandy soils, could realize the benefits of biochar as a climate-smart measure. Highlights The findings of research on biochar's effects on soil C sequestration, GHG mitigation, and crop production were summarized. The factors influencing the impact of biochar on soil functioning were reviewed. The effects of biochar on soil C sequestration and GHG mitigation in farmlands of China were quantified. [ABSTRACT FROM AUTHOR]

Considering the impacts of global climate change, paths for sustainable development are of particular importance. Biochar has multiple advantages, including but not limited to climate change mitigation, waste management, soil fertility improvement, and pollution remediation. Forest soils play a significant role in terrestrial ecosystems. The application of biochar in forest soils (ABFS) is therefore considered an essential tool for improving soil quality, capturing carbon, and reducing greenhouse gas emissions. The Web of Science Core Collection database was utilized for the bibliometric analysis of ABFS publications published between 2002 and 2022. Three bibliometric software were used to analyze bibliometrics, networks, and research directions for ABFS: Bibliometrix, VOSviewer, and CiteSpace. The analysis shows that research on ABFS is always rapidly developing. Research on ABFS is engaged globally in a complex network of collaborations, and the main research has occurred in China and the United States. Collaboration among authors is relatively diffuse. Research on ABFS involves interdisciplinary integration. In the early stages of research, the origin of biochar (history and boreal forests) and its characteristics (dynamics, nitrogen content, and chemical composition) were the focus of attention. As research progressed, more attention was given to ABFS (carbon, organic matter, vegetation, and heavy metals). Our research shows that while ABFS research has a certain history, its development trend has been consistently upward and shows no signs of declining. Thus, future research will likely concentrate on ABFS. Due to the complexity of biochar functions, ample research opportunities exist in ABFS. [ABSTRACT FROM AUTHOR]

Application of biochar amendments in agricultural systems has received much attention in recent years. In this study, we assess the 5‐year impacts of biochar application on soil water and plant interactions for an irrigated fresh market tomato (Solanum lycopersicum) and a rainfed pasture (Poaceae) cropping system. In particular, we focus on three varieties of locally produced biochar from agricultural waste materials—almond shell, walnut shell, and almond pruning residues that are pyrolyzed using a mobile pyrolysis unit. We used the soil hydrological model HYDRUS‐1D to explicitly track seasonal and annual soil water fluxes through changes in water retention, drainage, evaporation, and plant water uptake under biochar application. Modeling results show that the application of biochar at 5% increased soil water availability within the top 20 cm for a rainfed system, irrespective of biochar amendment type. This is clearly indicative of higher plant water uptake and greater water use efficiency (WUE) under biochar application. In contrast, a similar biochar amendment for the irrigated system did not affect WUE, instead reducing seasonal soil evaporation loss and thereby reducing irrigation demand. In both cropping systems, year‐to‐year variability in precipitation significantly impacted the total amount of water saved under biochar application with certain amendments retaining more water than others. Given that biochar application increased water retention irrespective of cropping systems, we further used a simple approach to determine yield trade‐off, if any, between control and biochar treatments. Our economic balance clearly demonstrates that the water saved by amending soil with biochar does not offset the yield disparity if compensated with carbon credits and therefore, application of biochar should be actively considered for both its direct and indirect benefits to potential greenhouse gas mitigation (e.g., diverting orchard waste from open burning), water savings, and soil health. Core Ideas: A soil hydrological model was used to evaluate the midterm (5‐year) effects of three biochar types, derived from local agriculture waste using a mobile pyrolyzer, on soil water and plant uptake dynamics.Two common cropping systems with different irrigation schemes were assessed using the model.Biochar application reduced total predicted soil evaporation in both systems.More agronomic benefits are observed in the rainfed system as compared to the irrigated system.Indirect benefits linked to biochar application (e.g., carbon credit) must be considered for economic feasibility. [ABSTRACT FROM AUTHOR]

Improving soil management to enhance soil carbon sequestration (SCS)—a cost-efficient carbon dioxide (CO2) removal approach—can result in co-benefits or trade-offs. Here we address this issue by setting up a modeling framework for Switzerland that combines soil carbon (C) storage, food production and agricultural greenhouse gas (GHG) emissions. The link to food production is crucial because crop types and livestock numbers influence soil organic C (SOC) stocks, through soil C inputs from plants and manure. We estimated SCS rates for the years 2020–2050 for three scenarios, each with two variants for biochar: cover cropping (0.30 t CO2 equivalents [CO2-eq] ha−1 yr−1), biochar addition (0.36–1.8 t CO2-eq ha−1 yr−1) and agroforestry-biochar addition (2.2–2.3 t CO2-eq ha−1 yr−1). Different limiting factors (land and biomass availability, population growth) affected SCS rates and indicated that they cannot be sustained until 2100 under all scenarios (cover cropping: 0.10 t CO2-eq ha−1 yr−1 [2051–2100]; biochar addition: 0.35–1.8 t CO2-eq ha−1 yr−1; agroforestry-biochar addition: 1.0–1.7 t CO2-eq ha−1 yr−1). This information together with the associated GHG emissions is critical for planning net zero strategies and highlights the importance of integrated assessments that capture links between SCS and the food system.

Biochar is a solid material enriched with carbon produced by the thermal transformation of organic raw materials under anoxic or anaerobic conditions. It not only has various environmental benefits including reducing greenhouse gas emissions, improving soil fertility, and sequestering atmospheric carbon, but also has the advantages of abundant precursors, low cost, and wide potential applications, thus gaining widespread attention. In recent years, researchers have been exploring new biomass precursors, improving and developing new preparation methods, and searching for more high-value and meaningful applications. Biochar has been extensively researched and utilized in many fields, and recently, it has also shown good industrial application prospects and potential application value in the printing field. In such a context, this article summarizes the typical preparation and modification methods of biochar, and also reviews its application in the printing field, to provide a reference for future work. [ABSTRACT FROM AUTHOR]

The maintenance of the extensive parks at National Agrarian La Molina University (UNALM) generates a large amount of forest biomass, with high treatment costs. For this reason, the pyrolysis of the forest biomass is an alternative for valorization, allowing proper management producing biochar. The aim of the research was to evaluate the stability of biochar at 300℃ and 500℃ from forest biomass of five predominant species at UNALM, Grevillea robusta, Schinus molle, Casuarina cunninghamiana, Ficus benjamina and Eucalyptus spp. To determine the stability of biochar produced, two methodologies were used (IBI and an adaptation of the López et al.(2010) method), for which organic, labile, oxidizable, recalcitrant carbon on biochar were determined. The results showed a decrease in biochar yield of 6.50% with an increasing pyrolysis temperature. Regarding physicochemical characteristics, the biochar produced was alkaline (pH above 8); besides, the pH and electrical conductivity increased with temperature, by 0.64 and 0.38 ds/m, respectively. However, in the case of nitrogen and ashes, the opposite occurred. It was concluded that all the biochar produced complied with the stability limits according to the applied methodologies, and BSM500 had the highest value of stability considering the applied methodologies. This may indicate that it could have the greatest sequestration of C once applied to the soil and also the reduction of emissions; for that reason, it would be important to carry out future research to estimate the potential for C sequestration in the long term. [ABSTRACT FROM AUTHOR]

Agriculture faces a significant challenge in maintaining crop production to meet the calorie demand of the ever-growing population because of limited arable land and climate change. This enforces a search for alternative multifarious agricultural-based solutions to meet the calorie demand. In search of alternatives, agricultural soil management has been highlighted and is expected to contribute to climate change mitigation through soil carbon sequestration and reduce greenhouse gas emissions through effective agricultural management practices. The addition of biochar to the soil significantly improves the soil nitrogen status, soil organic carbon, and phosphorus, with greater effects under the different tillage systems. This symbiosis association could further change the bacterial structure in the deeper soil layer which thus would be important to enhancing productivity, particularly in vertisols. Biochar also has an environmental risk and negative consequences. Heavy metals could be present in the final food products if we use contaminated raw materials to prepare biochar. However, there is a need to investigate biochar application under different climatic conditions, seasons, soil tillage systems, and crop types. These indicate that the positive effect of proper biochar fertilization on the physiology, yield formation, nutrient uptake, and soil health indicators substantiate the need to include biochar in the form of nutrients in the crop production sector, especially in light of the changing climate and soil tillage systems. [ABSTRACT FROM AUTHOR]

Feed additives belong to a number of climate change mitigation strategies being sought to reduce methane emissions in ruminants. In this study, the effect of biochar or biochar and urea supplementation on dairy cow performance and methane production was assessed. Eighteen cows were used in a 3 × 3 latin square design with three feeding groups: control with no supplementation (CO), biochar supplementation (BC, 200 g/day) and biochar and urea supplementation (BC + U, 200 g/day biochar and 90 g/day urea). All cows were fed a forage mixture ad libitum and 5 kg of concentrates per day on average. Methane emissions were measured in respiration chambers. Biochar as well as biochar and urea supplementation did not affect total dry matter, energy and utilisable protein intake. However, lignin intake was higher in the BC group and crude protein intake was higher in the BC + U group compared to the CO group. Supplementation of feed additives did not affect milk production and milk composition, except for the higher milk urea content in the BC + U group. Feed conversion, diet digestibility and methane production were not affected by feeding strategy. In conclusion, biochar supplementation does not reduce methane emissions, but it does not negatively affect dairy cow performance. [ABSTRACT FROM AUTHOR]

In agricultural activities, there is an increasing need for organic fertilizers to use nature-friendly materials used to fertilize the soil. Farmers have been using granular organic fertilizers made from composted or dried manure of cattle, poultry, pigs, ash, bone meal, and other materials for some time, but the quantities of these organic fertilizers are not large. Biochar is also being intensively studied as a material to improve soil quality and plant growth and reduce greenhouse gas emissions from soil. The suitability of cattle manure compost, poultry manure, biochar, and their combinations for granular fertilizers was analyzed in this work. The preparation of biochar for granulation may have differences compared to other organic materials due to the moisture content, fractional composition, bulk density, and other parameters of the granulated material, so this work examines the physical–mechanical and chemical properties of cattle and poultry manure and biochar raw material and the final granulated product. Research has found that the fractional composition of raw materials under investigation manure and biochar was up to 2 mm. The moisture content of the studied raw material varied from 8.97% in the case of poultry manure to 25.11% in the case of cattle manure compost. The lowest moisture content was obtained due to additional drying. The addition of biochar reduces the granule density in investigated cases. Poultry manure granules were the most mechanically stable, with a semi-static stability of 382.6 ± 78.08 N. After the addition of biochar, weaker binding properties were determined in the experimental granules. Analysis of the composition of elements shows that these granules can be used for fertilization or soil improvement. High concentrations of nitrogen (N), phosphorus (P), and potassium (K) were detected in the granules. The obtained results showed that it is appropriate to enrich the manure granules with biochar. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impacts of straw and biochar on greenhouse gas (GHG) emissions and grain yield in a double rice cropping system under optimal N fertilizer reduction. Conventional fertilization (CF) was used as the control group, and treatments included optimal fertilization and 15% less nitrogen (OF), together with straw (S) or biochar (B) applied under different fertilization conditions, namely CF + S, CF + B, OF + S, and OF + B. The effects of treatments on soil CH4 and N2O emissions were studied, and changes in soil physicochemical properties were analyzed. The results showed that relative to CF, CF + S and OF + S increased the cumulative CH4 emissions by 11.80% and 2.35%, respectively, while CF + B and OF + B resulted in significant reductions in cumulative CH4 emissions by 27.80% and 28.46%, respectively. Biochar was effective in reducing N2O emissions, and OF further increased the potential, with CF + B and OF + B achieving the best N2O reductions of 30.56% and 32.21%, respectively. Although OF reduced yields by 0.16%, this difference was within reasonable limits; the remaining treatments increased grain yields by 2.55% to 3.47%. CF + B and OF + B reduced the global warming potential (GWP) by 27.93% and 28.63%, respectively, and ultimately reduced the greenhouse gas emission intensity (GHGI) by 30.42% and 30.97%. Both straw and biochar increased the soil organic matter, NH4+-N, and NO3−-N contents, and biochar increased the soil pH, which may be the potential mechanism regulating soil GHG emissions. Overall, OF + B is beneficial for reducing GHG emissions and may be a better agronomic cropping pattern in double season rice growing areas. [ABSTRACT FROM AUTHOR]

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Agricultural waste can have a catastrophic impact on climate change, as it contributes significantly to greenhouse gas (GHG) emissions if not managed sustainably. Swine-digestate-manure-derived biochar may be one sustainable way to manage waste and tackle GHG emissions in temperate climatic conditions. The purpose of this study was to ascertain how such biochar could be used to reduce soil GHG emissions. Spring barley (Hordeum vulgare L.) and pea crops in 2020 and 2021, respectively, were treated with 25 t ha−1 of swine-digestate-manure-derived biochar (B1) and 120 kg ha−1 (N1) and 160 kg ha−1 (N2) of synthetic nitrogen fertilizer (ammonium nitrate). Biochar with or without nitrogen fertilizer substantially lowered GHG emissions compared to the control treatment (without any treatment) or treatments without biochar application. Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions were directly measured using static chamber technology. Cumulative emissions and global warming potential (GWP) followed the same trend and were significantly lowered in biochar-treated soils. The influences of soil and environmental parameters on GHG emissions were, therefore, investigated. A positive correlation was found between both moisture and temperature and GHG emissions. Thus, biochar made from swine digestate manure may be an effective organic amendment to reduce GHG emissions and address climate change challenges. [ABSTRACT FROM AUTHOR]

Biochar, known as "Black Gold", has become a novel approach with potential benefits for soil amendment, such as improving soil physicochemical properties, reducing greenhouse gas emissions, and enhancing soil fertility. The previous research studies mainly focus on exploring different methods for the improvement of biochar enriched nutrients as fertilizers; however, the migration and transformation mechanisms of these nutrients induced by biochar are yet to be extensively investigated. This paper provides an overview of recent advances in the application and mechanisms of biochar for soil amendment focusing on soil properties and nutrients improvement. Biochar positively alters microbial-mediated reactions in the soil C and N cycles, i.e., mineralization of C and N, and N2 fixation, thus enhancing maximizing C and N use efficiency and reducing the potential losses. Moreover, biochar provides reactive surfaces where P and K ions are retained in soil microbial biomass and in exchange sites, leading to increasing the availability of P and K to plants uptake. In addition, the toxic substances and potential ecological risks of biochar were also reviewed and discussed, thereby providing a baseline reference and guiding significance for future biochar applications as promising soil amendments. [ABSTRACT FROM AUTHOR]

Modified biochars have attracted attention for reducing greenhouse gas emissions in paddy fields. However, material screening difficulties and lengthy effect validation periods have restricted their development. We proposed a theoretical calculation method to guide short-term field trials in this study. Utilizing first-principles calculations, we determined that sodium ferrate-modified biochar (Fe@C) would limit methane (CH4) and nitrous oxide (N2O) emissions. Field trials confirmed that Fe@C increased rice yields and active organic carbon content in soil and reduced methane emissions and the global warming potential. However, applying sodium ferrate alone significantly reduced N2O emissions. Correlation analysis showed that methane was significantly negatively correlated with yield and the soil carbon pool labile index. N2O was significantly negatively correlated with urease activity, and significantly positively correlated with the soil carbon pool management index. Therefore, Fe@C provides a high-yielding management measure that enhances soil labile organic carbon. Additionally, its effects were controlled by the proportion of sodium ferrate. Our work provides a new strategy to guide the design of paddy field experiments via theoretical calculations, greatly shortening research time and providing solutions for carbon sequestration and emissions reduction. [ABSTRACT FROM AUTHOR]

A feedlot growing (77-d) and finishing (111-d) experiment was conducted to evaluate the effects of feeding biochar on steer performance, methane and carbon dioxide emissions, and carcass characteristics. Two treatments were evaluated, a control diet without biochar and the same diet with biochar included at 0.8% of dietary DM (growing) or 1.0% of dietary DM (finishing). The growing diet consisted of 40% corn silage, 40% wheat straw, 15% modified distillers grains plus solubles, and 5% supplement, with 0.8% biochar replacing fine ground corn in supplement. The finishing diet consisted of 55% high-moisture corn (HMC), 35% Sweet Bran, 5% wheat straw, and 5% supplement, with biochar replacing 1.0% HMC and added as an ingredient. Biochar was sourced from ponderosa pine wood waste (High Plains Biochar, Laramie, WY) and was 83% C with 426 m2/g surface area for both experiments. Crossbred steers were utilized in the growing (n = 160; initial BW = 363 kg; SD = 16 kg) and finishing (n = 128; initial; BW = 480 kg; SD = 17 kg) experiments, blocked by BW, and assigned randomly to 16 pens. Pens were assigned randomly to one of two treatments (biochar vs. control) with eight replications per treatment. Four pen replications per treatment were paired within BW block and rotated randomly through an emissions barn with two chambers (each treatment was evaluated simultaneously and for two rotations) to capture average weekly emissions of CH4 and CO2. Pen was the experimental unit and chamber was included as a fixed effect for emissions data. There were no statistical differences (P ≥ 0.23) in performance outcomes between treatments for the growing experiment. Dry matter intake (DMI; P < 0.01) and average daily gain (ADG; P = 0.02) were 2.2% and 5.9% lower for biochar-fed steers in the finishing experiment, respectively, resulting in a lighter hot carcass weight (P = 0.10) and lower calculated USDA yield grade (P = 0.02). Emissions of CH4 and CO2 were not affected by biochar inclusion in the growing (P ≥ 0.22) or finishing experiment (P ≥ 0.60). Results from these experiments show no indication that feeding biochar, supplemented at 0.8% (growing), and 1.0% (finishing) of the diet DM, reduces methane emissions in growing or finishing cattle. [ABSTRACT FROM AUTHOR]

Straw biochar is a commonly recognized agricultural amendment that can improve soil quality and reduce carbon emissions while sequestering soil carbon. However, the mechanisms underlying biochar's effects on annual soil carbon emissions in seasonally frozen soil areas and intrinsic drivers have not been clarified. Here, a 2-y field experiment was conducted to investigate the effects of different biochar dosages (0, 15, and 30, t ha−1; B0 (CK), B15, and B30, respectively) on carbon emissions (CO 2 and CH 4) microbial colony count, and soil-environment factors. The study period was the full annual cycle, including the freeze-thaw period (FTP) and the crop growth period (CP). Structural equation modeling (SEM) was developed to reveal the key drivers and potential mechanisms of biochar on carbon emissions. Biochar application reduced soil carbon emissions, with the reduction rate positively related to the biochar application rate (B30 best). During FTP, the reduction rate was 11.5% for CO 2 and 48.2% for CH 4. During CP, the reduction rate was 17.9% for CO 2 and 34.5% for CH 4. Overall, compared with CK, B30 treatment had a significant effect on reducing total soil carbon emissions (P < 0.05), with an average decrease of 16.7% during the two-year test period. The study also showed that for soils with continuous annual cycles (FTP and CP), carbon emissions were best observed from 10:00–13:00. After two years of freeze-thaw cycling, biochar continued to improve soil physical and chemical properties, thereby increasing soil microbial colony count. Compared with B0, the B30 treatment significantly increased the total colony count by 74.3% and 263.8% during FTP and CP (P < 0.05). Structural equation modeling (SEM) indicated that, with or without biochar application, the soil physicochemical properties directly or indirectly affected soil CO 2 and CH 4 emission fluxes through microbial colony count. The total effects of biochar application on CO 2 emission fluxes were 0.50 (P < 0.05) and 0.64 (P < 0.01), respectively, but there was no significant effect on CH 4 emission fluxes (P > 0.05). Among them, soil water content (SWC), soil temperature (ST) and soil organic carbon (SOC) were the main environmental determinants of CO 2 emission fluxes during the FTP and CP. The total effects were 0.57, 0.65, and 0.53, respectively. For CH 4 , SWC, soil salinity (SS) and actinomycete colony count were the main environmental factors affecting its emission. The total effects were 0.50, 0.45, 0.44, respectively. For freeze-thaw alternating soils, the application of biochar is a feasible option for addressing climate change through soil carbon sequestration and greenhouse gas emissions mitigation. Soil water-heat-salt-fertilization and microbial communities are important for soil carbon emissions as the reaction matrix and main participants of soil carbon and nitrogen biochemical transformation. • The addition of 30 t ha−1 biochar helped to significantly reduce annual soil carbon emissions (P < 0.05). • 10:00–13:00 is the best time to monitor annual freeze-thaw soil carbon emissions. • Soil water content (SWC), temperature and organic carbon are the main drivers of CO 2 emissions from anniversary soils. • SWC, salinity and actinomycete colony count are the main drivers of CH 4 emissions from anniversary soils. [ABSTRACT FROM AUTHOR]

Remediation activities, particularly in megasites, may induce substantial secondary environmental impacts that must be addressed for green and sustainable remediation (GSR) practices. Only limited studies are available quantitatively assessing the environmental footprint and environmental benefits of implementing Best Management Practices (BMPs) in megasite remediation. This study used the SiteWise™ tool, a quantitative environmental footprint assessment for scenario simulation and benefit quantification of BMPs, on a contaminated megasite in Hebei Province, China. We observed a considerable environmental footprint and energy from the remediation. Taking the final implementation alternative (Alt 1) as an example, which is characterized by combining multiple remediation techniques, the greenhouse gas (GHG) emissions reached 113,474 t, the energy used was 2,082,841 million metric British thermal units (MMBTU), and other air pollutant emissions (NOx, SOx, and PM 10) amounted to 856 t. Further BMP analyses highlighted the benefits of substituting the conventional solidification/stabilization agent with willow woodchip-based biochar, which could reduce GHG emissions by 50,806 t and energy used by 926,648 MMBTU. The overall environmental benefits of implementing all applicable BMPs in the remediation were significant, with a 66.85%, 50.15%, and 56.05% reduction in GHG emissions, energy used, and other air pollutants, respectively. Our study provides insights into quantifying the environmental footprint and exploring emission reduction pathways for contaminated megasite remediation. It also offers a feasible path for quantifying the environmental benefits of BMPs, promoting the development of GSR of contaminated sites. [Display omitted] • Quantifying environmental footprint for two remediation alternatives of contaminated megasite. • Simulations and environmental benefit quantification of multiple BMPs by the SiteWise™ tool. • Replacing traditional S/S agents with biochar is recognized as a highly effective BMP. • Implementation of all available BMPs has the potential to reduce GHG emissions by 66.85% at a contaminated megasite. [ABSTRACT FROM AUTHOR]

The total global food demand is expected to increase up to 50% between 2010 and 2050; hence, there is a clear need to increase plant productivity with little or no damage to the environment. In this respect, biochar is a carbon-rich material derived from the pyrolysis of organic matter at high temperatures with a limited oxygen supply, with different physicochemical characteristics that depend on the feedstock and pyrolysis conditions. When used as a soil amendment, it has shown many positive environmental effects such as carbon sequestration, reduction of greenhouse gas emissions, and soil improvement. Biochar application has also shown huge benefits when applied to agri-systems, among them, the improvement of plant growth either in optimal conditions or under abiotic or biotic stress. Several mechanisms, such as enhancing the soil microbial diversity and thus increasing soil nutrient-cycling functions, improving soil physicochemical properties, stimulating the microbial colonization, or increasing soil P, K, or N content, have been described to exert these positive effects on plant growth, either alone or in combination with other resources. In addition, it can also improve the plant antioxidant defenses, an evident advantage for plant growth under stress conditions. Although agricultural residues are generated from a wide variety of crops, cereals account for more than half of the world's harvested area. Yet, in this review, we will focus on biochar obtained from residues of the most common and relevant cereal crops in terms of global production (rice, wheat, maize, and barley) and in their use as recycled residues to stimulate plant growth. The harvesting and processing of these crops generate a vast number and variety of residues that could be locally recycled into valuable products such as biochar, reducing the waste management problem and accomplishing the circular economy premise. However, very scarce literature focused on the use of biochar from a crop to improve its own growth is available. Herein, we present an overview of the literature focused on this topic, compiling most of the studies and discussing the urgent need to deepen into the molecular mechanisms and pathways involved in the beneficial effects of biochar on plant productivity. [ABSTRACT FROM AUTHOR]

Biochar application has been considered as a promising solution to address the effects of modern agriculture on climate change. However, there is a lack of research on the biochar application of greenhouse gas emissions based on poor soils in Korean agricultural land. Therefore, this study aimed to evaluate the effects of biochar application according to different soil characteristics on soil organic carbon (SOC) improvement and greenhouse gas reduction. The incubation experiments were conducted for 49 days and used different feedstock (barley straw and poultry manure) and biochar application rates (0, 5, 10, and 20-ton ha−1) in four soil characteristics (upland, U; greenhouse, G; converted land, C; reclaimed land, R). The results of this study showed that the SOC increased significantly in all soils after biochar application. The increasing SOC rate was the highest in poor soil. Biochar 20-ton ha−1 treatment significantly reduced N2O emissions by 33.2% compared with the control. Barley straw biochar significantly reduced N2O emissions from all soils. Barley straw biochar decreased approximately 74.5% of N2O emissions compared with poultry manure biochar. Poultry manure biochar improved SOC and reduced N2O emissions in poor soil. However, in poultry manure biochar treatment in U and G soil, N2O emissions increased. In conclusion, barley straw biochar application was found to suppress N2O emissions and improve the SOC in all soil characteristics of agricultural land. In addition, the soil carbon storage effect and N2O reduction effect of biochar were the highest in poor soil. Thus, the biochar application can be a potential agricultural practice for improving soil quality and decreasing N2O emissions in domestic agricultural soil. [ABSTRACT FROM AUTHOR]

Biochar is a pyrolytic material with several environmental benefits such as reducing greenhouse gas emissions, sequestering atmospheric carbon and contrasting global warming. However, nowadays, it has moved to the forefront for its conductivity and electron transfer properties, finding applications in the fabrication of electrochemical platforms. In this field, researchers have focused on low-cost biomass capable of replacing more popular and expensive carbonaceous nanomaterials (i.e., graphene, nanotubes and quantum dots) in the realization of sensitive cost-effectiveness and eco-friendly electrochemical tools. This review discusses recent developments of biochar-modified screen-printed electrodes (SPEs). Special attention has been paid to biochar's manufacturing processes, electron-donating capabilities and sensing applications. Examples of representative works are introduced to explain the distinct roles of biochar in several electro-bioanalytical strategies. [ABSTRACT FROM AUTHOR]

Using livestock residues as alternative fertilizers is a sustainable practice which recycles nutrients that would otherwise be lost. However, organic fertilizers may have a large impact on N2O emissions, offsetting the beneficial effects of C sequestration. After four years from biochar application, greenhouse gas fluxes were monitored for two years from a Maize field fertilized with digestate, slurry, or urea, with and without biochar. The objectives of the present study were to assess (i) the climate feedback of using residues from the livestock chain as alternative fertilizers and (ii) the contribution of biochar in mitigating GHGs emissions, while increasing the organic C in soil. Digestate was shown to have the highest impact on CO2 and N2O emissions from soil, with respect to mineral fertilization (+29 and +142%), more than slurry (+21 and −5%), whereas both residues positively affected CH4 uptake (+5 and +14%, respectively). The maximum N2O peaks occurred between 7–20 days after fertilization, accounting for 61% of total emissions, on average. Biochar was effective in reducing N2O emissions derived from mineral fertilization and digestate (−54% and −17%, respectively). An excess of labile organic matter and N induced the highest CO2 emissions and N2O peaks, independent of—or even triggered by—biochar. Mitigation of GHG emissions, from soils fertilized with livestock chain residue, can be obtained using biochar, but with limitations dependent on (i) the quantity of organic matter added, (ii) its quality, and (iii) the time from application: those aspects that deserve further investigations. [ABSTRACT FROM AUTHOR]

Biochar is a carbonized material obtained from the pyrolysis of biomass produced in a limiting environment of zero or very low oxygen. Its interest lies in its versatility for different applications in the water treatment, soil pollution, mitigation of greenhouse gases, etc. The synergy of this product with other amendments such as compost has been studied for different applications in the soil, including environmental remediation, crop yield, etc. The aim of the research is to identify the relevant aspects in the scientific literature of biochar, compost and soil through a bibliometric analysis for which 753 articles were selected from the Scopus database, having as keywords "biochar", "compost" and "soil". This research used R software, specifically the package Bibliometrix, to analyze descriptive analysis, author sources, document metrics, citation, co-citation analysis, co-occurrence network, co-word analysis, and collaboration analysis. Results showed that Zhang Z is the author with the greatest number of documents, and with a higher H index. Science of The Total Environment, Bioresource Technology, and Agronomy are the 3 topmost relevant sources. The keywords according to bond strength and most frequent use were biochar (538 occurrences), composting (349 occurrences), compost (436 occurrences), charcoal (295 occurrences), soil (255 occurrences). China is the country with the most collaboration. It is hoped that the bibliometric review will help to identify current research trends and provide information on the application of biochar and compost in the soil. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mango pit biochar as an alternative fuel was first reported for ironmaking. • Biochar closest to pulverized coal was identified by principal component analysis. • Life cycle assessment unraveled the maximum reduction of GWP was 220 kg CO 2 eq/tHM. Biochar, produced by the pyrolysis of carbon–neutral biomass, has great potential to replace pulverized coal (PC) injection in blast furnace (BF) ironmaking. Herein, this study aimed to develop a low-ash and low-alkali metal biochar from mango pit (MP) and evaluate its environmental impact as an alternative fuel for BF ironmaking. This paper first studied the feasibility of mango pit biochar (MPB) as an alternative fuel. Compared with other preparation conditions, MPB prepared at 600 °C for 60 min (MPB-600–60) had the most similar fuel performance to PC, which was confirmed by principal component analysis (PCA). Moreover, MPB-600–60 exhibited lower ash and alkali metal content compared to PC. The co-combustion experiment demonstrated that MPB-600–60 could promote the combustion of mixed fuel, and the optimal combustibility was achieved when the addition ratio of MPB-600–60 was 80%. Comprehensive life cycle assessment (LCA) revealed that the reduction of global warming potential (GWP) amounted to 220 kg CO 2 eq/tHM if MPB 100% replaced PC. These results indicated that MPB could significantly reduce the greenhouse gas emissions and the environmental impact of BF ironmaking. This study provides a novel and promising approach for developing low-carbon and clean alternative fuels in BF ironmaking. [ABSTRACT FROM AUTHOR]

This study assessed the impact of different plant-derived biochar (cornstalk, rice husk, and sawdust) on bacterial community and functions for compost maturity and gaseous emissions during the composting of food waste. Results showed that all biochar strengthened organic biotransformation and caused a higher germination index on day 12 (over 100%), especially for rice husk biochar to enhance the growth of Thermobifida related to aerobic chemoheterotrophy. Rice husk biochar also achieved a relatively higher reduction efficiency of methane (85.8%) and ammonia (82.7%) emissions since its greater porous structure. Besides, the growth of Pseudomonas , Pusillimonas , and Desulfitibacter was restricted to constrict nitrate reduction, nitrite respiration, and sulfate respiration by optimized temperature and air permeability, thus reducing nitrous oxide and hydrogen sulfide emissions by 48.0–57.3% by biochar addition. Therefore, rice husk biochar experienced the optimal potential for maturity increment and gaseous emissions mitigation. [Display omitted] • Biochar achieved compost maturity of food waste in 12 days (GI ≥ 100%). • Biochar limited the growth of Pseudomonas , Pusillimonas , and Desulfitibacter. • Biochar decreased CH 4 , N 2 O, NH 3 , and H 2 S emissions by 48.0–93.6%. • Rice husk biochar favored Thermobifida growth to enhance aerobic chemoheterotrophy. • Rice husk biochar was more beneficial to advance maturity and gaseous reduction. [ABSTRACT FROM AUTHOR]

Biochar is a carbon-neutral tool for combating climate change. Artificial intelligence applications to estimate the biochar mitigation effect on greenhouse gases (GHGs) can assist scientists in making more informed solutions. However, there is also evidence indicating that biochar promotes, rather than reduces, N 2 O emissions. Thus, the effect of biochar on N 2 O remains uncertain in constructed wetlands (CWs), and there is not a characterization metric for this effect, which increases the difficulty and inaccuracy of biochar-driven alleviation effect projections. Here, we provide new insight by utilizing machine learning-based, tree-structured Parzen Estimator (TPE) optimization assisted by a meta-analysis to estimate the potency of biochar-driven N 2 O mitigation. We first synthesized datasets that contained 80 studies on global biochar-amended CWs. The mitigation effect size was then calculated and further introduced as a new metric. TPE optimization was then applied to automatically tune the hyperparameters of the built extreme gradient boosting (XGBoost) and random forest (RF), and the optimum TPE-XGBoost obtained adequately achieved a satisfactory prediction accuracy for N 2 O flux (R 2 = 91.90%, RPD = 3.57) and the effect size (R 2 = 92.61%, RPD = 3.59). Results indicated that a high influent chemical oxygen demand/total nitrogen (COD/TN) ratio and the COD removal efficiency interpreted by the Shapley value significantly enhanced the effect size contribution. COD/TN ratio made the most and the second greatest positive contributions among 22 input variables to N 2 O flux and to the effect size that were up to 18% and 14%, respectively. By combining with a structural equation model analysis, NH 4 +-N removal rate had significant negative direct effects on the N 2 O flux. This study implied that the application of granulated biochar derived from C-rich feedstocks would maximize the net climate benefit of N 2 O mitigation driven by biochar for future biochar-based CWs. [Display omitted] • TPE-optimized XGBoost is the state-of-the-art technology to predict N 2 O mitigation. • Effect size, a new metric of AutoML, characterized biochar-alleviating N 2 O efficacy. • A high influent COD/TN enhanced the biochar-driven N 2 O mitigation strength. • Granulated biochar derived from C-rich feedstocks would maximize N 2 O mitigation. [ABSTRACT FROM AUTHOR]

Negative Emissions Technologies (NETs) will be needed in order to achieve the net zero emissions targets being set by many countries. These technologies will offset the residual greenhouse gas emissions of sectors that are inherently difficult to decarbonize. NETs draw down carbon through different physical, chemical, or biological pathways, and transfer it for storage to other environmental compartments. Examples of these techniques include afforestation, Biochar application, BioEnergy with Carbon Capture and Storage (BECCS), enhanced weathering, and Direct Air Capture (DAC). The large-scale deployment of NETs will be constrained by the footprints they apply to limited resources such as land, water, energy, and nutrients. In this work, a superstructure-based Linear Programming (LP) model is developed to optimize the carbon drawdown of integrated NET deployment under resource constraints. Results show that varying the target negative emissions and resource constraints affect the NETs portfolio and total cost. [ABSTRACT FROM AUTHOR]

This paper critically reviewed the current knowledge and challenges of rice husk biochar (RHB) production and its effects on soil properties, plant growth, immobilization of heavy metals, reduction of nutrient leaching and mitigation of greenhouse gas emissions. The characteristics of RHBs produced at various pyrolysis temperatures were discussed and compared to biochars derived from other agro- industrial wastes. RHBs produced at higher pyrolysis temperatures show lower hydrogen/carbon ratio, which suggests the presence of higher aromatic carbon compounds. The increase of pyrolysis temperature also results in production of RHBs with higher ash content, lower yield and higher surface area. RHB usually has higher silicon and ash contents and lower carbon content compared to biochars derived from other feedstocks at the same pyrolysis conditions. Although it depends on soil type, RHB application can improve soil organic carbon content, cation exchange capacity, available K concentration, bulk density and microbial activity. The effect of RHB on soil aggregation mainly depends on soil texture. The growth of different crops is also enhanced by application of RHB. RHB addition to soil can immobilize heavy metals and herbicides and reduce their bioavailability. RHB application shows a significant capacity in reduction of nitrate leaching, although its magnitude depends on the biochar application rate and soil biogeochemical characteristics. Use of RHB, especially in paddy fields, shows a promising mitigation effect on greenhouse gas (CH 4 , CO 2 and N 2 O) emissions. Although RHB characteristics are also related to other factors such as pyrolysis heating rate and residence time, its performance for specific applications (e.g. carbon sequestration, pH amendment) can be manipulated by adjusting the pyrolysis temperature. More research is needed on long-term field applications of RHB to fully understand the advantages and disadvantages of RHB as a soil amendment. [ABSTRACT FROM AUTHOR]

Within Australia, approximately 6.4% of total greenhouse gas emissions are from animal methane (CH4) derived from enteric fermentation. Mitigation of ruminant CH4 is a key concept in support of sustainable agriculture production; dietary manipulations a viable strategy to lower CH4 release during enteric fermentation. In order to determine the effects of dose response of biochar and wood vinegar supplementation on fermentation parameters and CH4 production, this study utilized in vitro batch culture incubations. It is hypothesized that the addition of either biochar or wood vinegar will successfully reduce enteric CH4 emissions without negative modification of other fermentation parameters. Three feed substrates (vegetable mixed ration, maize silage, and winter pasture) were separated into treatments containing either biochar at 0%, 0.5%, 1%, 2%, and 4% DM replacing substrate (w/w basis), or wood vinegar at 0%, 0.25%, 0.5%, 1%, and 2% into incubation media volume (v/v). At 6, 12, and 24 hours after inoculation, total gas volume, and methane (CH4 %) were measured. Volatile fatty acid (VFA) concentrations, media pH, and in vitro dry matter digestibility were measured at 24 hours. Biochar at various dosages had no effect (P > 0.05) on fermentation characteristics other than decreased in vitro dry matter digestibility (IVDMD; P = 0.01) at 2% and 4% (DM basis) inclusion. Similar to biochar, dose response of wood vinegar had no effect on in vitro fermentation characteristics. However, feed substrate had major effects on all fermentation parameters (P = 0.01) where winter pasture > vegetable mixed ration > maize silage for all recorded fermentation characteristics. Biochar and wood vinegar supplementation were ineffectual in mitigating CH4 production or modifying fermentation characteristics, thus rejecting the initial hypothesis. These results suggest the use of biochar is not an effective tool for methane mitigation in ruminant livestock and infers that studies previously reporting success must better define the systemic mechanisms responsible for the reduction in CH4. [ABSTRACT FROM AUTHOR]

Biochar application into soil has potential as a means for reducing soil greenhouse gas emissions and climate mitigation strategy. In this study, we evaluated the impact of two doses of biochar (10 and 20 t.ha−1) applied in 2014, combined with three fertilization levels (N0, N1, N2) on carbon dioxide (CO2) in field conditions during the growing season (April – October) in 2018. The field site is located in the Nitra region of Slovakia – Malanta. The soil in the field was classified as a silt loam Haplic Luvisol. There was not found any statistically significant (P <0.05) decreasing effect of biochar with or without N-fertilizer after four years of its application on average daily and cumulative CO2 emissions, while the CO2 emissions increased with additional N-fertilizer. Biochar decreased (insignificantly) the daily and cumulative CO2 emissions only in the treatments without N-fertilization and in the treatment fertilized with higher level of biochar application (20 t.ha−1) and N-fertilizer (80 kg.N.ha−1). According to these results it can be concluded that the biochar applied to soil is not able to reduce CO2 emissions after four years of its application when it is combined with usual agriculture practices which include N-fertilization. [ABSTRACT FROM AUTHOR]

Biochar as a prospective renewable energy candidate could be incorporated into the iron and steel production system to replace part of fossil fuels and reduce high-intensity greenhouse gas emissions. However, great uncertainties still exist on biochar's emission reduction capacity and economic feasibility, depending on different biochar precursors, substitution scenarios, energy consumption of biochar production and financial cost. This study aimed to explore the optimized substitution strategies concerning the above issues. A systematic carbon accounting was performed by material flow analysis method (MFA). Two biochar incorporated iron and steel production routes, integrated production route (BF-BOF) and short production route (EAF), which took the proportion of 71.5% and 28.2% in worldwide production, were considered. CO 2 Supply Curve (CSC) was conducted to carry out a quantitative economic viability analysis of biochar substitution under carbon emission trading schemes (ETS). Results showed that compared with straw-based biochar, wood-based biochar showed stronger carbon reduction capacity of 1.47 t CO 2e (CO 2-equivalent) /t crude steel, and the reduction potential reached 66.94% mostly. Among all the steel production processes, Blast furnace in BF-BOF route had the largest emission contribution proportion (72.06%), achieving the best GWP100 reduction potential of 73.66%. The incorporation of wood-based biochar in sintering (−0.037 yuan/t CO 2e) was selected as the scenario with both reduction potential and economic viability. If the scenario was fully implemented in China, it could reduce 2.01 million tons of CO 2e in 2021. This study would play a vital role in guiding iron and steel industry for biochar substituted fuels. [Display omitted] • Modern self-heating biochar production is considered in fuels substitution. • Wood-based biochar stands out in the emission reduction capacity of GWP100. • Biochar fuels substitution can reduce 66.94% CO 2e /t crude steel of GWP100. • Blast furnace process contributes 73.66% of the GWP100 reduction potential. • Implementation of wood-based biochar in sintering is the most economical route. [ABSTRACT FROM AUTHOR]

Nitrogen (N) fertilization profoundly improves crop agronomic yield but triggers reactive N (Nr) loss into the environment. Nitrous (N 2 O) and ammonia (NH 3) emissions are the main Nr species that affect climate change and eco-environmental health. Biochar is considered a promising soil amendment, and its efficacy on individual Nr gas emission reduction has been widely reported. However, the interactions and trade-offs between these two Nr species after biochar addition have not been comprehensively analysed. The influencing factors, such as biochar characteristics, environmental conditions, and management measures, remain uncertain. Therefore, 35 publications (145 paired observations) were selected for a meta-analysis to explore the simultaneous mitigation potential of biochar on N 2 O and NH 3 emissions after its application on arable soil. The results showed that biochar application significantly reduced N 2 O emission by 7.09% while having no significant effect on NH 3 volatilisation. Using biochar with a low pH, moderate BET, or pyrolyzed under moderate temperatures could jointly mitigate N 2 O and NH 3 emissions. Additionally, applying biochar to soils with moderate soil organic carbon, high soil total nitrogen, or low cation exchange capacity showed similar responses. The machine-learning model suggested that biochar pH is a dominating moderator of its efficacy in mitigating N 2 O and NH 3 emissions simultaneously. The findings of this study have major implications for biochar application management and aid the further realisation of the multifunctionality of biochar application in agriculture, which could boost agronomic production while lowering environmental costs. [Display omitted] • Biochar amendment could yield simultaneous N 2 O and NH 3 emissions reduction. • Biochar pH was a key factor to achieve jointed mitigation of NH 3 and N 2 O. • Soil properties and agricultural management affect biochar mitigation efficiency. [ABSTRACT FROM AUTHOR]

Following the Paris Agreement's climate targets and the modelling community's scenarios of how to reach them, carbon dioxide removal is gaining increasing importance in national climate policies. This is also the case in Denmark – considered by itself and others a climate frontrunner – where biochar is envisioned to cover 10% of the 2030 reduction goal. However, apart from research experiments and test sites, biochar is at the time of research not employed in Denmark, raising the question how it came to constitute a large part of the national goal. This paper explores how biochar, as a method for carbon removal, comes into being as a relevant solution in Danish climate policy, and what this means for emission reduction efforts. Through document analysis, participatory observation, field visits and semi-structured interviews, I employ the framework of the dramaturgical regime and analyse how biochar is enacted as a climate solution through policy documents, conferences, media and network meetings. Here the concept of enactment indicates that different people's actions are not overtly coordinated, and the effects of such actions are not necessarily fully intentional, but they are nevertheless political. I argue that through different scientific, administrative, political, and media practices, biochar is enacted as a viable climate solution that enables the continuation of current forms of production and consumption. As biochar likely substitutes for emission reductions and is in risk of failing to deliver the anticipated amount of carbon removals, the enactment of biochar as a climate solution in Danish climate policy possibly constitutes a case of mitigation deterrence. • Biochar is enacted as a relevant solution in Danish climate policy. • This occurs in policy documents, conferences, media and network meetings. • Enactments enable a continuation of current forms of production and consumption. • Including biochar in Danish climate policy is possibly a case of mitigation deterrence. • Enactments can show how mitigation deterrence can come about as an emergent effect. [ABSTRACT FROM AUTHOR]

As the regulator of constructed wetlands (CWs), biochar is often used to enhance pollutant removal and reduce greenhouse gas emission. Biochar is proved to have certain effects on microbial populations, but its effect on the aggregation of microbial flocs and the formation of biofilms in the CWs has not been thoroughly investigated. Therefore, the above topics were studied in this paper by adding a certain proportion of biochar in aerated subsurface flow constructed wetlands. The results indicated that after adding biochar in the CWs, pollutant removal was enhanced and the removal rate of NH 4 +-N was increased from 80.76% to 99.43%. The proportion of hydrophobic components in extracellular polymeric substances (EPS) was reduced by adding biochar from 0.0044 to 0.0038, and the affinity of EPS on CH 3 -SAM was reduced from 5.736 L/g to 2.496 L/g. The weakened hydrophobic and the reduced affinity of EPS caused the initial attachment of microorganisms to be inhibited. The relative abundance of Chloroflexi was decreased after adding biochar, reducing the dense structural skeleton of biofilm aggregates. Correspondingly, the abundance of Bacteroidetes was increased, promoting EPS degradation. Biochar addition helped to increase the proportion of catalytic active proteins in extracellular proteins and decrease the proportion of binding active proteins, hindering the combination of extracellular proteins and macromolecules to form microbial aggregates. Additionally, the proportions of three extracellular protein structures promoting microbial aggregation, including aggregated chain, β-sheet, and 3-turn helix, were decreased to 23.83%, 38.37% and 7.76%, respectively, while the proportions of random coil and antiparallel β-sheet that inhibited microbial aggregation were increased to 14.11% and 8.11%, respectively. An interesting conclusion from the experimental results is that biochar not only can enhance pollutants removal, but also has the potential of alleviating biological clogging in CWs, which is of great significance to realize the sustainable operation and improve the life cycle of CWs. [Display omitted] • Biochar reduced the hydrophobicity of extracellular polymeric substances (EPS). • Extracellular protein composition of EPS was altered by biochar. • Biochar addition induced changes in the extracellular protein secondary structure. • Biochar addition improved composition and structure of extracellular proteins. • Biochar has the potential to alleviate biological clogging in constructed wetlands. [ABSTRACT FROM AUTHOR]

The mitigation of greenhouse gas (GHG) emissions and water usage optimization in rice cultivation is challenging for many agricultural countries, including Thailand, who have set goals of reaching net zero emissions and coping with droughts caused by climate change. Alternate wetting and drying (AWD) and biochar application are possible practices for achieving cleaner rice production through reduction of GHG emissions and water consumption. However, these methods' potential varies by site, especially in areas with limited control of water levels. This study assessed the effects of AWD at different drying levels (10, 15, and 20 cm below the soil surface) and rice straw biochar on GHG emissions, yield production, water use, soil characteristics, and economic aspects. This study was conducted over two rice cultivation seasons: a major season in 2022 and a second season in 2023 at a field in Kalasin Province, northeastern Thailand. Using AWD and biochar reduced annual GHG emissions by 48.2% and 8.01%, respectively. Deeper drying levels of AWD showed greater mitigation potential than shallow levels. The combination of AWD and biochar had additional potential for GHG mitigation, however, this impact did not show statistical change as compared to their separate potentials. The adoption of AWD and biochar could also maintain the amount of rice yield compared to traditional practice. All levels of AWD saved irrigation water consumption by an average of 16.8% per season; the highest potential was observed in AWD at 10 cm below the soil surface. Biochar improved soil health after two seasons by enhancing soil pH and organic carbon sequestration. The combination of AWD and biochar did not additionally augment the capacity in water saving of AWD or soil improvement of biochar. The AWD water regime also did not increase net profits, while biochar decreased net profits due to the required investment in biochar production. Using AWD is a feasible way to mitigate GHG emissions and save water without affecting rice productivity and net profits in northeastern Thailand. [Display omitted] • Alternate wetting and drying (AWD) mitigated greenhouse gas emissions by 48.2%. • AWD reduced irrigation water use by an average of 16.8%. • AWD at 15 cm of drying level without biochar is suggested as a mitigation tool. • Rice straw biochar showed the significant impact on soil organic carbon stock. [ABSTRACT FROM AUTHOR]

Biochar is a promising soil additive for use in support of sustainable crop production. However, the high level of heterogeneity in biochar properties and the variations in soil composition present significant challenges to the successful uptake of biochar technologies in diverse agricultural soils. An improved understanding of the mechanisms that contribute to biochar–soil interactions is required to address issues related to climate change and cultivation practices. This review summarizes biochar modification approaches (physical, chemical, and biochar-based organic composites) and discusses the potential role of biochar in sustainable crop production and soil resiliency, including the degradation of soil organic matter, the improvement of soil quality, and reductions in greenhouse gas emissions. Biochar design is crucial to successful soil remediation, particularly with regard to issues arising from soil structure and composition related to crop production. Given the wide variety of feedstocks for biochar production and the resultant high surface heterogeneity, greater efforts are required to optimize biochar surface functionality and porosity through appropriate modifications. The design and establishment of these approaches and methods are essential for the future utilization of biochar as an effective soil additive to promote sustainable crop production. [ABSTRACT FROM AUTHOR]