Effects of Rice Straw Application on Methane Emission from Rice Paddy Fields

Methane emission in soil is caused by the decomposition of organic matter under highly anaerobic conditions. Rice paddy fields are a major source of methane emission, resulting from biological and physicochemical processes affected by various factors such as the agricultural techniques, climate, and soil properties. To evaluate the roles of soil particle, rice straw application and plowing time on methane production from rice paddy, methane emissions during the rice cultivation season were investigated in two different soil textures (sandy clay loam, sandy loam). Treatments of each soil were divided into NPK only (non organic treatment) and tillage after rice straw application. The methane emission flux in the rice straw application treatment was recorded, 4.36 kg ha–1 day–1 in sandy loam and 4.85 kg ha–1 day–1 in sandy clay loam. In case of NPK only treatment, 3.30 kg ha–1 day–1 in sandy loam and 3.20 kg ha–1 day–1 in sandy clay loam. As a result, increase of methane emission by rice straw application was higher in sandy clay loam soil than in sandy loam soil.