The objective of this study was to explore the relationship between the soil bacterial community (i.e. structure and molecular ecological network) and environmental evolution in long-term continuous cropping field.

In this study, soil samples were collected from two 12-year continuous cropping fields (GD with continuous cropping disorder and healthy YA) in Liuyang, Hunan Province. The bacterial community were analysed using high-throughput sequencing of 16S rRNA gene amplicons, molecular ecological network was constructed using molecular ecological network analyses (MENA), and both were related to the soil physicochemical properties.

The results showed that the total nitrogen and available phosphorus in GD were significantly higher, while the nitrate nitrogen and available potassium in GD soil were significantly lower than that in YA (p < 0.05). The soil bacterial community diversity was higher in GD than YA, and the bacterial community structure showed significant difference between GD and YA (p < 0.01). The bacterial community was significantly constrained by the soil pH and available phosphorus. The ecological network was more complex in GD than YA, which was mainly reflected in the modules containing energy metabolism, carbon cycle and nitrogen cycle functions.

In conclusion, continuous cropping caused significant changes in the soil bacterial community diversity and the structure and ecological network, which might affect the deterioration of soil physicochemical properties and soil fertility, and therefore, affect crop growth and development.