Title: ABUNDANCE OF METHANOGENS IN FLOODED RICE SOILS AND SURVIVAL OF METHANOGENS IN AIR- DRIED SOILS OF PADDY FIELD OF ZHEJIANG, CHINA
Authors: Brahima Traore, Min Hang, Fasse Samake, Chen Meici and Amadou Babana
Abstract: Methane (CH4) emissions from Chinese paddy soil (Zhejiang province) were measured over the rice growing seasons. Emissions of methane were high during two periods (05 days after peak tillering and 07 days after heading flowering stage). The amounts of methanogenic microbes, including hydrolytic fermentative, hydrogen producing acetogenic and methanogenic bacteria, were measured during the different growth stages of rice. The results showed that the amounts of hydrolytic fermentative bacteria increased or decreased with the growth of rice but that of hydrogen-producing acetogenic bacteria and methanogenic increased with the growth of rice. The amounts of methanogens decreased from 1.1 x 106 g-1dry soil after 15 days to 0.4 x102 g-1 dry soil after 1 year in air dried condition. It was obvious that obligatory anaerobic methanogenic bacteria were very sensitive to air ( O2). The obligate anaerobic methanogenic bacteria which were most sensitive to air ( O2 ) ,could survive in air-dried soil stored for long time. Flooding (or water saturation) and high moisture content appeared to be an important condition for the increased methanogens amounts in soil. No significant differences between the amounts of methanogens in different depths of soil were observed 0-10; 10-15; 15-20.