Deep vertical rotary tillage increases the diversity of bacterial communities and alters the bacterial network structure in soil planted to corn

Abstract

Deep vertical rotary tillage (DVRT) is a novel technique; however, its influence on soil bacterial diversity and community structure remains unclear. Herein, it was hypothesized that this tillage method significantly improves the bacterial diversity and alters the bacterial community structure and therefore it supports enhanced soil ecosystem functions in cultivated land. We investigated the soil bacterial communities and performed molecular ecological network analysis of cultivated land soils under different tillage regimes using high-throughput 16S rRNA gene Illumina sequencing. Soil samples were collected from the experimental field under 2 treatments: DVRT and conventional rotary tillage (CT) in Shizuishan City, Ningxia, China, in a 2-year field experiment. The α-diversity indices showed that DVRT resulted in higher bacterial diversity. In addition, the principal coordinate analysis results revealed a clear separation among the groups of cultivated land soils under the 2 treatment regimes. The key physicochemical factors that significantly influenced bacterial diversity and community structure were pH and total potassium concentration. The network analysis indicated that the bacterial network of DVRT soils consisted of more functionally interrelated bacterial modules than that of soils under CT, and the topological roles of characteristic bacteria and key bacteria were also different. In relation to CT, the relative abundances of organisms belonging to the functional groups of “Xenobiotics biodegradation and metabolism”, “Signal transduction”, and “Metabolism of cofactors and vitamins” were significantly increased in cultivated land soils under DVRT. It was concluded that DVRT treatment could improve bacterial diversity, alter the bacterial network structure, and enhance potential ecosystem functions in soils of cultivated land.