Studies on the Changes of Soil Microbial Communities under Peanuts Continuous Cropping

Changes in microbial communities of rhizosphere and bulk soil during different periods of continuous cropping years were researched by pot experiments in network.The results showed that the bacteria and actinomycetes quantities obviously decreased,and the fungi quantities obviously increased with the increase of the continuous cropping years.The bacteria quantities of the four treatments in rhizosphere soil were the single-peak curves which increased firstly and decreased subsequently,and their differences existed in the peak time: five continuous cropping years' treatment was in pot-setting stage,while the others were in blossom stage.As for the treatment with one continuous cropping year,the dynamics of fungi quantities in rhizosphere soil increased firstly and decreased subsequently and finally increased,and the peak was in blossom stage.The other treatments were the single-peak curves which increased firstly and decreased subsequently.The dynamics of actinomycetes quantities in the treatments with three continuous cropping years and control were relatively identical during the whole growth periods,which generally presented the trend of increasing firstly and then decreasing and reached the peak in the pot-setting stage.The dynamics of actinomycetes quantities in the treatments of one year's or five years' continuous cropping were relatively identical,which generally presented the trend of increase-decrease-slow increase and peaked in the blossom stage.