摘要
目前的研究结果表明,我国稻田甲烷排放通量大约在7.8—60mg/m^2·h。稻田甲烷的排放包含着甲烷在水田土壤中的生成和从土壤向大气释放这样两个过程。前者是通过土壤中微生物活动分解复杂的有机物质,在渍水还原条件(氧化还原电位低于-200mv)下,由产甲烷菌最后转化形成甲烷;后者主要是通过水稻植株向大气释放,只有少量通过气泡或分子扩散从水田土壤通过田面水层向大气排放。显然,稻田甲烷的生成、排放是一个以生物学过程为中心,并与土壤环境、土表水层和大气环境的一些物理、化学条件密切相关的过程。土壤温度、pH值、水稻品种的生物学特性及稻田的水浆管理、施肥措施等等都会影响稻田甲烷的排放。只有研究并掌握稻田甲烷排放的机理及其影响因素,才能真正做到在争取水稻优质、高产的同时,抑制或减少甲烷的排放。
Methane is an important greenhouse gas. According to the estimation of IPCC, the methane emission from rice paddies was about 20% of the total methane e-mission. Studies from China, one of major rice producing countries , showed that the methane emission flux from rice paddies in China varied from 7. 8 to 60mg/m2· h. The methane emission from rice paddies actually consists of two processes, the formation of methane in paddy soils and the release to the atmosphere. Methanogen providing anaerobic condition in water logged paddy (soil Eh value below -200mv) plays a key role for the methane formation. The methane emission from soil to the atmosphere is mostly through rice plants, only small amounts of methane is released across the water-air interface via bobbles or molecular diffusion. Therefore, the methane formation and emission is mainly a biological process. Some physical and chemical conditions of paddy soil, paddy water and atmo Sphere, such as temperature, pH, flooding period and application of organic manure and chemical fertilizer, greatly influence this process. With the understanding of the mechanism of methane emission from rice paddies, the methane emission rate can be reduced along with a good rice production.
出处
《生态与农村环境学报》
CAS
CSCD
1993年第S1期40-42,59-60,共5页
Journal of Ecology and Rural Environment
关键词
甲烷
稻田
排放机制
抑制排放
methane , rice paddy , emission mechanism , e- mission reduction
