Impacts of Soil Organic Matter on Microbial Community of Paddy Soils in Gyeongnam Province

Agricultural management of paddy soil depends on the effects of soil microbial activities. The present study evaluated the soil microbial community of 25 paddy soils in Gyeongnam Province by fatty acid methyl ester (FAME). The average of microbial communities in paddy soils were 32.2% of total bacteria, 16.7% of Gram-negative bacteria, 12.9% of Gram-positive bacteria, 2.0% of actinomycetes, 14.9% of fungi, and 1.3% of arbuscular mycorrhizal fungi. The communities of total bacteria (34.9%) and Gram-negative bacteria (19.4%) in soils with 30∼35 g kg -1 of organic matter were significantly larger than those in soils with other organic matter levels. However, soils with 20∼30 g kg-1 of organic matter had significantly low ratio of cy17:0 to 16:1ω7c and cy19:0 to 18:1ω7c as compared with soils with 30∼35 g kg -1 of organic matter, indicating microbial stress decreased (p -1 of organic matter were responsible for strong effect on microbial biomass and stress in paddy fields.