Effects of continuous cropping on tobacco-planting soil bacterial community diversity in typical tobaccogrowing areas of Yunnan Province

Abstract

This study aimed to clarify the influence of continuous cropping on the tobacco-planting soil bacterial community in typical tobacco-growing areas of Yunnan Province. The V3~V4 region of soil bacterial 16S rDNA was determined using high-throughput MiSeq sequencing and the influence of continuous cropping on abundance and diversity of the soil bacterial community was analyzed in relation to the main chemical characteristics. The results showed that with the extension of continuous cropping duration, the number of endemic bacteria and the abundance and diversity of the bacterial community showed an increasing trend in the Qujing tobacco-growing area, whereas the Honghe tobacco-growing area showed an decreasing trend. The number of endemic bacteria in the Wenshan tobacco-growing area first showed a decreasing trend and subsequently, an increasing trend, whereas the abundance and diversity of the bacterial community showed an increasing trend. At the phylum level, the effective sequences obtained from continuous cropping soils in the three tobacco-growing ecological areas showed 94.32%~99.31% sequence identity to the bacterial groups Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, Gemmatimonadetes, and Planctomycetes, which were the dominant community groups(relative abundance>4.0%). The abundance and diversity of the dominant phylum were spatially and temporally heterogeneous in different ecozones with the extension of continuous cropping duration. Soil pH and available K, organic matter, and available P content were significantly correlated with bacterial community distribution in the continuous cropping soil. The results provide a theoretical basis for reducing challenges owing to continuous cropping by revealing the differences in soil microflora and physical and chemical environment in typical tobacco-growing areas of Yunnan Province.

Topics & Concepts