Review on the Long-term and Short-term Effects of Biochar Addition on Soil Greenhouse Gas Emissions

Abstract

Increasing concentrations of greenhouse gases in the atmosphere caused by human activities are the main cause of climate warming. Global warming is a severe challenge confronted by human society today. Reducing greenhouse gas emissions and increasing carbon sinks are the keys to addressing climate warming. Biochar addition is considered to be a promising way to reduce greenhouse gas emissions and increase carbon sinks, due to its unique physical, chemical, and biological properties. Therefore, it is of great significance to study the effects of biochar on soil greenhouse gas emissions to mitigate the greenhouse effect and achieve "carbon neutrality." The long-term and short-term effects of biochar on soil greenhouse gas emissions and their influencing mechanism were reviewed. It was found that the effects of biochar on soil greenhouse gas emissions varied with the types of biochar feedstock, pyrolysis temperature, application ratio, and soil and vegetable types. In addition, due to the different aging times and modes and cultivation methods, the mitigation effect of aged biochar on soil greenhouse gas could be enhanced or weakened or even disappeared. Further, based on the deficiencies of the previous research, the direction and focus of future research on the effects of biochar on soil greenhouse gas emissions were analyzed and prospected. It was proposed to strengthen simultaneous research on the effects of biochar on CO2, N2O, and CH4 emissions; reducing greenhouse gas emissions and carbon sequestration; different aging modes and cultivation methods of biochar; and revealing the influencing mechanism at the process level, through exploring the effects of biochar on soil carbon and nitrogen dynamics and tracing the source of greenhouse gases using 13C and 15N tracer technology.