Abstract
Agricultural disturbance has significantly boosted soil greenhouse gas (GHG) emissions such as methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O). Biochar application is a potential option for regulating soil GHG emissions. However, the effects of biochar application on soil GHG emissions are variable among different environmental conditions. In this study, a dataset based on 129 published papers was used to quantify the effect sizes of biochar application on soil GHG emissions. Overall, biochar application significantly increased soil CH4 and CO2 emissions by an average of 15% and 16% but decreased soil N2O emissions by an average of 38%. The response ratio of biochar applications on soil GHG emissions was significantly different under various management strategies, biochar characteristics, and soil properties. The relative influence of biochar characteristics differed among soil GHG emissions, with the overall contribution of biochar characteristics to soil GHG emissions ranging from 29% (N2O) to 71% (CO2). Soil pH, the biochar C:N ratio, and the biochar application rate were the most influential variables on soil CH4, CO2, and N2O emissions, respectively. With biochar application, global warming potential (impact of the emission of different greenhouse gases on their radiative forcing by agricultural practices) and the intensity of greenhouse gas emissions (emission rate of a given pollutant relative to the intensity of a specific activity) significantly decreased, and crop yield greatly increased, with an average response ratio of 23%, 41%, and 21%, respectively. Our findings provide a scientific basis for reducing soil GHG emissions and increasing crop yield through biochar application.
Highlights
The current global warming trend is of great significance since it is most likely the result of anthropogenic activities, and its control has become a challenge [1]
Data were collected from 129 published articles through November 2019; the focus of the analyzed papers was on the effects of biochar application on soil greenhouse gas (GHG) emissions and crop yield
Five criteria were used: (1) treatments and the control group must be included in the same independent trials; (2) either crop yield or soil GHG emissions must be present in both treatments and control groups; (3) the data of soil GHG emissions must come from topsoil (0–20 cm); (4) the means, standard deviation, and number of replicates must be presented or calculated from the reported data; (5) the number of trial design iterations must be higher than two
Summary
The current global warming trend is of great significance since it is most likely the result of anthropogenic activities, and its control has become a challenge [1]. As a soil amendment, could be an effective strategy for mitigating GHG emissions and increasing crop yield. Biochar characteristics and soil properties greatly influence soil GHG emissions and crop productivity [8,9]. The positive effect of biochar application on soil CH4 and CO2 emissions could be attributed to the increase in belowground primary productivity and the inhibition of soil methanotrophs [14], while reduced soil CH4 and CO2 emissions may be associated with decreased enzymatic activities and the ratio of methanogenic to methanotrophic archaea [15]. Different raw materials and pyrolysis temperatures used in the production of biochar may have various effects on soil GHG emissions and crop productivity [17]
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