稻田甲烷排放机理和调控技术

The Mechanism of Methane Release in Paddy Field and Technique for Control

分别在温室和田间进行甲烷排放测定。结果表明：稻田土壤氧化还原电位低于-180mV时，甲烷排放量明显上升；稻田甲烷排放途径：3／4从水稻排出，1／4从土灌排出；宽窄行“双龙出海”插秧＋养萍、垄畦栽水稻＋养萍可分别比常规稻作减少甲烷排放量21．8％和42．3％；稻田放养一定量的革胡子鲶能提高上壤氧化还原电位，减少甲烷排放，放养量以2250kg·hm－1为宜。放养量过大会增加甲烷排放；稻田放养鱼、萍，“双龙出海”插秧方式，通过人工调控技术，使稻田系统内部形成有利于甲烷排放的稻田持续农业模式，结果甲烷排放量比常规稻作减少34．6％。

The rnethane release was tested in green house and paddy field respectively.The results showed that when oxidation ch reduction potential in paddy soil is lower than -180 mV, the methane - releasing amount being increased significantly . The methane releasing amount in paddy field were consist of 3/4 from rice plants and 1/4 from soil. In the fields where plant rice seedlings in double wide-narrow rows spacing method plus growing azolla,mound planting plus growing azolla methane-releasing amounts was re-duced by 21. 8% and 42. 3% respectively compared with traditional rice cultivation method. Ralsing certain amount of carfish in paddy field can increase oxidation reduction potential of paddy soil thus decrease the methane-releasing amount. The artificial control-ling technique that raising fish, growing azolla in paddy field, plus using alternative wide narrow row spacing made it possible to depress the methane releasing amount in paddy field ecosystem. To compare with the traditional cropping system, the methane release was decreased by 34.6%.