Simulating no-tillage effects on crop yield and greenhouse gas emissions in Kentucky corn and soybean cropping systems: 1980–2018

Abstract Soil management alters physical, chemical and biological soil properties. Stress application affects microbiological activity and habitats for microorganisms in the root zone and causes soil degradation. We hypothesized that stress application results in altered greenhouse gas emissions if soil strength is exceeded. In the experiments, soil management dependent greenhouse gas emissions of intact soil cores (no, reduced, conventional tillages) were determined using two experimental setups; CO2 emissions were determined with: a dynamic measurement system, and a static chamber method before and after a vertical soil stress had been applied. For the latter CH4 and N2O emissions were analyzed additionally. Stress dependent effects can be summed as follows: In the elastic deformation range microbiological activity increased in conventional tillage soil and decreased in reduced tillage and no tillage. Beyond the precompression stress a release of formerly protected soil organic carbon and an almost total loss of CH4 oxidizability occurred. Only swelling and shrinkage of no tillage and reduced tillage regenerated their microhabitat function. Thus, the direct link between soil strength and microbial activity can be applied as a marker for soil rigidity and the transition to new disequilibria concerning microbial activity and composition.

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Quantifying the Effects of Biochar Application on Greenhouse Gas Emissions from Agricultural Soils: A Global Meta-Analysis

Sustainability ◽

10.3390/su12083436 ◽

2020 ◽

Vol 12 (8) ◽

pp. 3436 ◽

Cited By ~ 2

Author(s):

Qi Zhang ◽

Jing Xiao ◽

Jianhui Xue ◽

Lang Zhang

Keyword(s):

Greenhouse Gas Emissions ◽

Greenhouse Gas ◽

Crop Yield ◽

Radiative Forcing ◽

Specific Activity ◽

C:N Ratio ◽

Ghg Emissions ◽

N2o Emissions ◽

Response Ratio ◽

Gas Emissions

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.

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