Changes of soil microbial communities under different land use patterns in the agro-pastoral ecotone of northern China

Due to the aggravation of human-land conflicts and changes in national policies, China's northern agricultural and pastoral areas present a wide variety of land-use types, including natural grassland, artificial grassland, shrubland, woodland and maize farmland. However, the composition of soil microbial communities under different land use types is not well understood due to the interference of many different factors. Here, we compared soil microbial communities under these five typical land use types within the agricultural and pastoral areas of northern China. Our results showed that land use practices have a considerable impact on the structure of soil microbial communities. Specifically, there were significant differences in the diversity and composition of both bacteria and fungi under different land use types. The complexity of microbial network structure also showed significant differences with land use practices. The reduction in the number of nodes and edges under the two highly intensively managed land uses, artificial grassland and maize farmland, led to a decrease in complexity, while the high number of nodes and edges under the other three land uses with low intensive management tended to make the network structure more complex. By analyzing the correlation between soil properties (including soil physicochemical properties, soil nutrients, microbiomass carbon and nitrogen) and soil microbial communities, we discovered that although microbial taxa were correlated to some extent with soil environmental factors, these factors were not sufficient to explain microbial community differences between land uses. Understanding differences in soil microbial communities within the agro-pastoral areas of northern China is critical for determining the most effective land management strategies and conserving microbial diversity at the regional level.