Methane emissions from rice paddies: a process study summary

Irrigated rice cultivation is one of the largest sources (approximately 15–20% of the annual total) of atmospheric methane, a potent greenhouse gas. This review examines the results of work performed over the past six years in which we have investigated the processes leading to the emission of methane from irrigated rice cultivation. These studies describe the daily and seasonal effects on methane production and emission of different planting dates, water management, organic amendments, soil texture, and cultivar choice. Because rice agriculture is one of the few sources of methane where emission reduction through management is considered possible, it promises to be a critical focus of mitigation efforts. We have identified several potential management practices for rice cultivation that may stabilize or reduce the emission of methane even in the face of future increased grain production necessary to meet the demands of an expanding world population.