Synthesis Report on Greenhouse Gas Emissions from Agroecosystems: GHG Cycling, Microbial Processes, and Strategies for GHG Mitigation

Agriculture accounts for 10–12% of global greenhouse gas emissions, mainly through the release of carbon dioxide, methane, and nitrous oxide. This synthesis summarizes findings from several studies on GHG emissions in agricultural systems. Rice paddies are major sources of methane, with emissions lowered by organic amendments like vermicompost compared to conventional fertilizers. Agricultural soils contribute up to 80% of anthropogenic nitrous oxide emissions, chiefly from fertilizer use. Livestock enteric fermentation produces considerable methane. Soil GHG fluxes are driven by microbial activities like nitrification and denitrification, regulated by environmental factors including moisture, temperature, and pH. While organic nutrient sources can increase GHG emissions, they enhance soil carbon storage and quality compared to inorganic fertilizers alone. Integrated nutrient management and conservation practices like reduced tillage, crop rotation, and integration of cover crops, residues, or livestock offer significant potential to mitigate agricultural GHG emissions while maintaining yields. However, optimizing climate-smart practices requires site-specific adaptation based on soil, climate, and cropping conditions. Overall, sustainable land management can reduce agriculture’s climate impact, but more research is needed to support widespread farmer adoption.