Dynamic changes in the rhizosphere bacterial community in monoculture and intercropped corn and soybean during various crop growth stages

Abstract Although rhizosphere microorganisms have been studied for a long time, rhizosphere microbial communities based on monoculture and intercropped soybean and corn have rarely been studied. To define the effect of crop monoculture and intercropping on soil physicochemical properties and rhizosphere microbial communities, field experiments were conducted using corn and soybean cultivars at five different crop growth stages. The pH and soil organic matter (SOM) were the key factors affecting crop rhizosphere soil microorganisms. The content of available phosphorus (AP) in the intercropped soybean/corn soil samples was higher than that in the monoculture soil samples at five different growth stages. The content of available cadmium (ACd) in monoculture soybean rhizosphere soil samples decreased and then increased, but the intercropped soybean soil samples indicated an opposite trend. Proteobacteria, Chloroflexi, Acidobacteria, Actinobacteria and Firmicutes were the dominant phyla in the soybean and corn rhizosphere soil samples. Crops of the same plant species showed little difference in the bacterial community diversity under the two planting modes. The results showed that the cadmium content in cadmium-polluted soil could be reduced by the soybean/corn intercropping system. The crop rhizosphere bacterial community is not only regulated by the crop itself but also influenced by the planting pattern.