水稻田的甲烷释放及其生物学机理

RELEASE OF METHANE IN PADDY SOIL ADN ITS BIOLOGICAL MECHANISM

本文报道采用土柱法和田间原位法研究淹水稻田甲烷释放特性及其微生物学机理。结果表明,早稻以分蘖盛期时甲烷释放量最大,以后逐渐减少;晚稻从分蘖开始逐渐增加,至分蘖盛期、末期时达到最大,孕穗期急剧减少,生长后期又有所回升。晚间和上午释放的甲烷量较多,中午(10∶00—14∶00)几乎无释放,下午又有少量释放。不同施肥区的水稻甲烷释放量明显不同,以施猪粪区为最高,次为施尿素区,不施肥区最低。但各施肥区在整个水稻不同生育期的甲烷释放趋势则完全一致,以分蘖盛、末期释放量最大。稻田释放的甲烷主要是通过植株释放,可占总释放量85%以上,行株间土壤释放量不多,田间水释放极少。产甲烷细菌附存于根表而不进入根内组织。根系土壤中产甲烷微生物类群、厌氧性纤维素分解细菌和甲烷氧化细菌及总挥发性有机酸含量都明显高于行株间土壤。

The characteristics and biological mechanism of methane reliase in paddy soil were studied by the soil column and in situ field methods. The resuIts obtained showed that the amounts of methane released were the highest during full-tillering stage of both early and late rice; the amount of methane released was higher during night and morning and lower during afternoon: fertilizers could stimulate the release of methane in paddy soil and the methane release of organic manure plot was more than that of urea plot; there active part of methane formation was the root system which was undisturbed and combined closely with soil; more than 80% of methane was released by rice plants: methanogenic bacteria adhered to surface of roots. The result also showed that the amounts of methanogenic bacteria, anaerobic celluloclastic and methane-oxidizing bacteria as well as TVFA were higher in rhizosphere soil were than in nonrhizosphere soil.