Relationship between CH4 and N2O emissions and related microorganism populations in paddy soils under different water management regimes

Methanogens,methanotrophs,nitrifiers and denitrifiers are the important microorganisms in the production and consumption of CH 4 and N 2O in soil. In order to understand the microbial processes related to the two greenhouse gases in paddy soil,the four bacteria groups in phaeozem (Hailun) and burozem (Shenyang) were surveyed during rice growth season by using MPN counting technique. The CH 4 and N 2O emissions were measured with closed chamber method. Two different water management regimes,i.e.,continual irrigation and intermittent irrigation,were used for the two paddy soils. The results of multiple regression analysis showed that there was a significantly positive correlation between CH 4 emission and methanogen population in both phaeozem and burozem under two water management regimes. In the soil of Shenyang,there was a significantly positive correlation between CH 4 emission and methanotroph population. The N 2O emission was significantly correlated to the denitrifier population in both phaeozem and burozem under intermittent irrigation,and in the soil of Shenyang,there was a significantly positive correlation between N 2O emission and nitrifier population under two water managements.