Abstract
Background: Continuous cropping obstacles from sweet potato are widespread, which seriously reduce the yield and quality, restrict the sustainable development of sweet potato industry. Bacteria are the most abundant in rhizospheric soil and have a certain relationship with continuous cropping obstacles. However, there are few reports on how continuous cropping affected the bacterial community structure in the rhizospheric soil of sweet potato. In this study, high-throughput sequencing technique was used to explore the changes of rhizospheric soil bacterial community structure of different sweet potato varieties, and the correlation between soil characteristics and this bacterial community after continuous cropping, so as to provide a theoretical basis for the prevention and control of sweet potato continuous cropping obstacles.Results: After two years of continuous cropping, the results showed that (1) the dominant bacteria phlya in rhizospheric soils from both Xushu18 and Yizi138 were Proteobacteria, Acidobacteria, and Actinobacteria. The most dominant genus was Subgroup 6_norank. Significant changes in the relative abundance of rhizospheric soil bacteria were observed for two sweet potato varieties. (2) Bacterial richness and diversity indexes of rhizospheric soil from Xushu18 were higher than those from Yizi138 after continuous cropping. Moreover, the beneficial Lysobacter and Bacillus were more prevalent in Xushu18, but Yizi138 contained more harmful Gemmatimonadetes. (3) Soil pH decreased after continuous cropping, and redundancy analysis showed that soil pH was significantly correlated with bacterial community. Spearman’s rank correlations coefficients analysis demonstrated that pH was positively correlated with Planctomycetes and Acidobacteria, and negatively correlated with Actinobacteria and Firmicutes.Conclusions: After continuous cropping of sweet potato, the bacterial community structure and physicochemical properties in the rhizospheric soil were unbalanced, and the changes of different sweet potato varieties were different. The contents of Lysobacter and Bacillus were higher in the sweet potato variety resistant to continuous cropping. It provides a basis for the development of special microbial fertilizer for sweet potatoes to alleviate continuous cropping obstacle.
Effects of Continuous Cropping on Bacterial Community Structure in Rhizospheric Soil of Sweet Potato