Biochar application in management of paddy crop production and methane mitigation

Abstract

Paddy agriculture is one of the major anthropogenic sources of methane (CH4) emission at global level. A decrease in CH4 release in the atmosphere from paddy fields can add significantly to the management of global warming and climate change. Biochar production and application in agriculture prepared from crop straw has been proposed as one of the effective countermeasure to mitigate the greenhouse gas emissions (GHGs) during farming. Biochar, a co-product of a controlled pyrolysis process, can be used as a tool to offset GHGs emissions and as a soil conditioner. Biochar application increased rice productivity, soil pH, soil organic carbon, total N but decreased soil bulk density in the long term. Recent studies have confirmed that the use of biochar in paddy agriculture has the capability to minimise the CH4 production, but its essential mechanism has yet to be clarified. The additions of biochar to the agriculture soil showed higher CH4 consumption because it improves soil aeration and porosity and enhances methanotrophs performance. However, further investigations are needed to evaluate the effect of biochar addition on net CH4 emissions and consumptions, respectively, by methanogens and methanotrophs. Long-term experiments should be conducted to monitor any changes over the years on the influence of biochar amendments on soil-methanotrophs-paddy systems.