Compositional and structural changes in soil microbial communities in response to straw mulching and plant revegetation in an abandoned artificial pasture in Northeast China

The overgrazing and overutilization of pastures can lead to serious degradation that can be restored through proper management practices. However, little is known about the dynamic changes in soil microbial communities during such restoration processes. Therefore, we investigated the characteristics of changes in soil microbial communities during straw mulching and plant revegetation processes in an abandoned artificial pasture in Northeast China. We used 16S rRNA gene and ITS sequencing to analyze the composition and diversity of soil bacterial and fungal communities under control, straw mulching, Leymus chinensis revegetation, and straw mulching + L. chinensis revegetation treatments. Straw mulching was effective in enhancing the contents of total N, alkali-hydrolyzable N, and available P in soils under plant revegetation. The alpha diversity indexes of both bacterial and fungal communities decreased under all treatments. Plant revegetation and straw mulching had an additive effect on the bacterial community composition; their combination increased the absolute abundances of copiotrophic phyla, including Proteobacteria, Actinobacteria, Gemmatimonadetes, Bacteroidetes, and Acidobacteria. However, the response of the fungal community to these treatments was minimal. Moreover, redundancy analysis showed that the soil total N was the most important soil factor affecting the bacterial and fungal community compositions. Our findings highlight the additive effects of straw mulching and revegetation on soil microhabitats and soil bacterial communities, which enhanced the soil quality in an abandoned artificial pasture in Northeast China. •The change characteristics of soil microbial community during the restoration of an abandoned artificial pasture in Northeast China were studied.•The combination of straw mulching and plant revegetation had an additive effect on the soil microbial community composition and diversity as well as on soil properties.•The bacterial community responded more sensitively than the fungal community to restoration, and the bacterial communities changed from oligotrophic to copiotrophic communities.•Soil total nitrogen mainly contributed to explain the bacterial and fungal community compositions.