Plant types shape soil microbial composition, diversity, function, and co-occurrence patterns in cultivated land of a karst area

Plants can alter microbial communities through root exudates, and change the characteristics of the soil. However, the relationship between soil microbial communities and environmental factors is not well understood. Here, we studied bacterial and fungal communities and their relationships with environmental factors. We integrated data of environmental factors, microbial composition, diversity, functional prediction, and co-occurrence network from uncultivated, maize, cabbage, and cocozelle soils in a karst area of Southwest China. Soil bacterial and fungal community composition differed with plant types. Maize soil had more taxa and greater alpha diversity of bacteria and fungi than other soils. In maize soil, the relative abundance of Actinobacteria and Ascomycota was significantly lower than that in uncultivated soil, while its contents of soil organic matter (OM), alkali-hydrolyzable nitrogen, and total nitrogen (TN) showed the opposite trend. These indicators were not significantly different between cabbage and cocozelle soils. The results of the Mantel test and the RDA analysis indicated that TN and OM were important drivers of bacterial and fungal communities. Functional prediction and network analysis showed that maize soil had a high nitrogen fixation capacity and a complex and stable network. To summarize, maize soil not had a low relative abundance of Ascomycota and high content of TN and OM, nitrogen fixation ability, and a rich microbial community. Therefore, cultivating maize is suitable for improving soil microbial community. These findings might help in formulating a reasonable cultivation management program to prevent land degradation in the karst areas.

Automated summary

Plants can change soil characteristics and microbial communities through root exudates. This study found that soil bacterial and fungal communities differed with plant types, with maize soil having higher diversity and abundance. Soil organic matter, alkali-hydrolyzable nitrogen, and total nitrogen were important drivers of bacterial and fungal communities. Functional prediction and network analysis showed that maize soil had high nitrogen fixation capacity and a complex and stable network. Therefore, cultivating maize is beneficial for improving soil microbial communities and preventing land degradation in karst areas.