Methane Emissions In Paddy Soil Under Two Ways Of Irrigation

Methane as one of paddy green house gas, plays an important role in global warming, and rice paddies have been identified as major methane(CH4) source induced by human activities. Rice water-saving irrigation is an important direction for future agricultural development, and covered film drip irrigation is an important water-saving irrigation mode. In order to explore the influence of soil moisture regulation on methane(CH4) emissions under water-saving irrigation and look for an irrigation mode for rice that would save water while simultaneously limiting CH4 emissions, the regularity of CH4 emissions from paddy fields under controlled irrigation was analyzed. This study is based on previous studies, using a static camera obscura-gas chromatography to measure CH4 emissions in covered film drip irrigation rice fields and normal paddy field in situ observations to an alysis of the dynamic response of the rice fields CH4 emissions. Experiments were divided into three treatment: drip I, drip II and flooding. The local high-yielding cultivars jihan 1 which is drought resisting was used to analysis the methane emissions from rice paddy. The results are as follows:(1) methane emission flux from rice fields under covered film drip irrigation is less than methane emission flux in flooded conditions;(2) methane emission flux in drip I is more than that in drip II, suggesting water in soil is one of major factors which affect CH4 emission;(3) methane emissions trend under three conditions are broadly consistent, and emission peaks are in early tillering,tillering medium-term and jointing booting, suggesting that covered film drip irrigation did not affect methane emissions trend in rice vegetative period. These results suggested that the soil moisture regulation under film drip irrigation resulted in a series of dewatering in paddy field and changed the oxygen supply in soil rooting profile, finally reduced the total CH4 emissions from paddy fields. The film drip irrigation mode could significantly reduce CH4 emissions from paddy fields.