Long‑term Continuous-cropping System Altered the Microbial Communities and Nutrient Cycles in Bijie, Guizhou province

Abstract

Abstract Understanding the response of microbial communities and their potential functions is essential for the long-term continuous-cropping agroecosystems. However, there are few studies on the interaction between soil physicochemical factors and microbial community dynamics in agroecosystems under long-term continuous-cropping conditions. We investigated the physicochemical properties, metabolites, and microbial diversity of rhizosphere soils in which tobacco was cropped continuously for 0, 5, and 20 years. The results showed that the bacterial diversity significantly increased and then decreased with the duration of continuous-cropping. In addition, the fungal diversity increased significantly, indicating that the change in fungi may shift the nutrient cycles of continuous-cropping karst agroecosystems. In this study, soil pH and the contents of available phosphorus (AP) and available nitrogen (AN) were the key environmental factors leading to changes in the structures and functions of microbial communities in continuous-cropping soil. The metabolites released by tobacco, such as palmitic acid, 3-hydroxypropionic acid, stearic acid, and hippuric acid, reduced soil pH.