Potential role of biochars in decreasing soil acidification - A critical review

Dai, Zhongmin; Zhang, Xiaojie; Tang, Caixian; Muhammad, Niaz; Wu, Jianjun; Brookes, Philip C.; Xu, Jianming

doi:10.1016/j.scitotenv.2016.12.169

Cited by 435 publications

(205 citation statements)

References 139 publications

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“…Biochars are alkaline (pH > 7.0) and can increase soil pH due to high‐ash contents (Dai et al, ; Yuan, Xu, & Zhang, ). The pH increase of soil may promote soil denitrifying activity, nosZ abundance and stimulate the whole denitrification process (Chen et al, ; Lehmann & Joseph, ).…”

Section: Discussionmentioning

confidence: 99%

Easily mineralizable carbon in manure‐based biochar added to a soil influences N₂O emissions and microbial‐N cycling genes

Dai

Zhang

et al. 2018

Land Degrad Dev

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Manure‐based biochar is an effective amendment to increase both carbon sequestration and the fertility of degraded soils, whereas the responses of N2O emissions and microbial‐N cycling genes to its application and the underlying mechanisms are poorly understood. Here, four biochars were produced under two pyrolysis temperatures (300 and 700°C) and with two organic C extraction procedures (water and acetone extraction). The resulting biochars were either with relative enrichment or depletion in easily mineralizable carbon (EMC) compared with recalcitrant C. We added biochars, with urea and sodium nitrate, to a degraded red soil and incubated the amended soils at moisture levels of 60% and 130% field capacity. All the biochars decreased nitrification gene abundance, that is, amoA. Biochars with EMC had greater stimulatory effects on the abundance of denitrification genes (nirK, nirS, and nosZ) and N2O emission, regardless of moisture level and N form, compared with biochar without EMC. Biochar‐induced microbial activity, biochar aliphatics, and alkyl groups correlated positively with N2O emission and denitrification gene abundance. The water dissolved organic C of biochar facilitated the conversion of N2O to N2, whereas the acetone extractable C fraction postponed the completion of denitrification. In conclusion, the N2O emission and denitrification gene abundance increased with decreasing biochar aromaticity and increasing EMC content. Our study emphasizes that the EMC supply in manure‐based biochars also importantly mediates soil N2O emission and microbial N cycling genes, adding to current understanding of influencing factors such as biochar pH, porosity, N availability, and redox property.

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Section: Discussionmentioning

confidence: 99%

Easily mineralizable carbon in manure‐based biochar added to a soil influences N₂O emissions and microbial‐N cycling genes

Dai

Zhang

et al. 2018

Land Degrad Dev

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“…The soil pH did not show any significant drop at the end of 49 days of experimental period. Acidic soils lead to a higher metal biotoxicity risk and subsequent carbon depletion than alkaline soils (Bolan et al, 2014;Sheng et al, 2016;Dai et al, 2017).…”

Section: Influence Of Biochar On Heavy Metal Availabilitymentioning

confidence: 99%

Biochar modulates heavy metal toxicity and improves microbial carbon use efficiency in soil

Seshadri

Sarkar

et al. 2018

Science of The Total Environment

204

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Soil organic carbon is essential to improve soil fertility and ecosystem functioning. Soil microorganisms contribute significantly to the carbon transformation and immobilisation processes. However, microorganisms are sensitive to environmental stresses such as heavy metals. Applying amendments, such as biochar, to contaminated soils can alleviate the metal toxicity and add carbon inputs. In this study, Cd and Pb spiked soils treated with macadamia nutshell biochar (5% w/w) were monitored during a 49days incubation period. Microbial phospholipid fatty acids (PLFAs) were extracted and analysed as biomarkers in order to identify the microbial community composition. Soil properties, metal bioavailability, microbial respiration, and microbial biomass carbon were measured after the incubation period. Microbial carbon use efficiency (CUE) was calculated from the ratio of carbon incorporated into microbial biomass to the carbon mineralised. Total PLFA concentration decreased to a greater extent in metal contaminated soils than uncontaminated soils. Microbial CUE also decreased due to metal toxicity. However, biochar addition alleviated the metal toxicity, and increased total PLFA concentration. Both microbial respiration and biomass carbon increased due to biochar application, and CUE was significantly (p<0.01) higher in biochar treated soils than untreated soils. Heavy metals reduced the microbial carbon sequestration in contaminated soils by negatively influencing the CUE. The improvement of CUE through biochar addition in the contaminated soils could be attributed to the decrease in metal bioavailability, thereby mitigating the biotoxicity to soil microorganisms.

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“…Thus, the need to identify effective soil amendments to decrease soil acidification or correct soil pH has become crucially important for sustainable forest development in Sweden. The incorporation of biochars into acid soils can increase soil pH by up to two units (Dai et al., ), as well as raise soil organic carbon level that consequently improve forest productivity and enhance economic returns of forest industry. Therefore, converting paper mill sludge into biochar in a large‐scale application can deliver a range of benefits to Sweden such as contribution in climate change mitigation, reduction in soil acidification, and increase in tree growth and wood productions.…”

Section: Development Of Biochar In Swedish Forest Ecosystemsmentioning

confidence: 99%

Environmental analysis of producing biochar and energy recovery from pulp and paper mill biosludge

Mohammadi

Sandberg

Venkatesh

et al. 2019

J of Industrial Ecology

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Sweden is one of the largest exporters of pulp and paper products in the world. It follows that huge quantities of sludge rich in carbonaceous organic material and containing heavy metals are generated. This paper carried out a comparative environmental analysis of three different technologies, which can be adopted to produce biochar and recover energy from the biosludge, using landfilling as the reference case. These three thermochemical biosludge management systems—using incineration, pyrolysis, and hydrothermal carbonization (HTC)—were modeled using life cycle assessment (LCA). Heat generated in the incineration process (System A) was considered to be for captive consumption within the kraft pulp mills. It was assumed that the biochars—pyrochar and hydrochar—produced from pyrolysis (System B) and HTC (System C), respectively, were added to the forest soils. The LCA results show that all the alternative systems considerably improve the environmental performance of biosludge management, relative to landfilling. For all systems, there are net reductions in greenhouse gas emissions (–0.89, –1.43, and –1.13 tonnes CO2‐equivalent per tonne dry matter biosludge in Systems A, B, and C, respectively). System B resulted in the lowest potential eutrophication and terrestrial ecotoxicity impacts, whereas System C had the least acidification potential. The results of this analysis show that, from an environmental point of view, biochar soil amendment as an alternative method for handling pulp and paper mill biosludge is preferable to energy recovery. However, an optimal biochar system needs to factor in the social and economic contexts as well.

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Potential role of biochars in decreasing soil acidification - A critical review

Cited by 435 publications

References 139 publications

Easily mineralizable carbon in manure‐based biochar added to a soil influences N₂O emissions and microbial‐N cycling genes

Easily mineralizable carbon in manure‐based biochar added to a soil influences N₂O emissions and microbial‐N cycling genes

Biochar modulates heavy metal toxicity and improves microbial carbon use efficiency in soil

Environmental analysis of producing biochar and energy recovery from pulp and paper mill biosludge

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Potential role of biochars in decreasing soil acidification - A critical review

Cited by 435 publications

References 139 publications

Easily mineralizable carbon in manure‐based biochar added to a soil influences N2O emissions and microbial‐N cycling genes

Easily mineralizable carbon in manure‐based biochar added to a soil influences N2O emissions and microbial‐N cycling genes

Biochar modulates heavy metal toxicity and improves microbial carbon use efficiency in soil

Environmental analysis of producing biochar and energy recovery from pulp and paper mill biosludge

Contact Info

Product

Resources

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Easily mineralizable carbon in manure‐based biochar added to a soil influences N₂O emissions and microbial‐N cycling genes

Easily mineralizable carbon in manure‐based biochar added to a soil influences N₂O emissions and microbial‐N cycling genes