Tillage Practice Impacts on the Carbon Sequestration Potential of Topsoil Microbial Communities in an Agricultural Field

Soil microorganisms are the core force driving the conversion of plant residues into soil organic carbon (SOC). Identifying the changes in soil microorganism responses to tillage practices is a key step in understanding the SOC sequestration potential. The aim of this study is to assess the impacts of different tillage practices on microbial communities and functions in agricultural soils. A field experiment involving no tillage (NT), rotary tillage (RT), and deep tillage (DT) in winter wheat-summer maize double cropping was performed to determine the structure of the microbial community and its functions using metagenomics. We found that tillage practices changed the composition of soil microbial communities and their functions related to the C cycle. The relative abundance of fungi in DT was significantly higher than that of the NT and RT treatments and primarily facilitated the growth of the fungi community. Moreover, DT treatment increased the relative abundance of genes involved in carbohydrate transport and metabolism genes and carbohydrate metabolism pathway genes, in addition to those encoding carbohydrate-binding modules. Therefore, we concluded that DT increases the transformation potential of straw-C to SOC in the North China Plain where large amounts of wheat and maize straw are returned to the field every year.