Effects of soybean continuous cropping on rhisphere culturable microorganisms and physicochemical properties of soil

【Objective】Effects of soybean continuous cropping on soil microorganisms and physicochemical properties were studied.【Method】With the rhisphere soils of cropping and rotation soybean as test materials, the following indexes including soil microorganisms, bacterial physiological groups, physicochemical properties were investigated during the different growth stages of soybean.【Result and conclusion】The results showed that there were significant influences of continuous and alternate cropping on soil microorganisms. The number of bacteria, actinomycetes decreased, especially the reduction of ammonifying bacteria, nitrifying bacteria, aerobic nitrogen-fixing bacteria, cellulose-decomposing bacteria, but fungi amount increased. The content order of soil available nitrogen and potassium was rotation cropping>alternate cropping>1-year continuous cropping>2-year continuous cropping >3-year continuous cropping. The content order of soil available phosphorus was rotation cropping>alternate cropping>1-year continuous cropping>3-year continuous cropping >2-year continuous cropping. The mean mass diameter and geometric mean diameter of rotation soil were significantly higher than alternate and continuous cropping.