Response of soil bacterial community structure and co-occurrence network topology properties to soil physicochemical properties in long-term continuous cropping farmland

Abstract:

[Objective] To explore the relationship of soil bacterial community structure and molecular ecological network with soil environment in farmland with long-term continuous cropping. [Methods] In this study, high-throughput sequencing of 16S rRNA gene was performed to reveal the correlation of soil microbial community structure and topological properties of molecular ecological network with soil physicochemical properties of two 12-year continuous cropping fields (GD with continuous cropping obstacle and healthy YA) in Liuyang, Hunan province. [Results] The content of total nitrogen and available phosphorus in GD soil was significantly higher than that in YA soil, while the content of nitrate nitrogen and available potassium was significantly lower than that in YA soil (P<0.05). The bacterial diversity of GD soil was higher than that in YA soil, and the soil bacterial community structure was significantly different between GD and YA (P<0.01), which was related to soil pH and available phosphorus content. Soil bacterial community in GD had a more complex ecological network than that in YA, as manifested in the functional modules of energy metabolism, carbon cycle, and nitrogen cycle. [Conclusion] Continuous cropping can cause changes in soil bacterial community diversity, structure, and ecological network, which may be closely related to the deterioration of soil physicochemical properties and soil fertility, and affects crop growth and development.

Key words:long-term continuous cropping;soil microorganisms;bacterial community structure;molecular ecological network;biogeochemical cycle