SRA

Plants and soil microbes are intricately linked and agricultural production relies heavily on soil microbially mediated ecosystem services. However, the effects of plant diversity (richness, relative abundance, and composition) on microbial community diversity and function are still unclear. To better inform agricultural grassland management, it is essential to understand the effects of plant diversity on soil microbial communities, especially in intensively managed systems. Between May and September 2019, we conducted a field experiment on an established, intensively managed agricultural grassland to investigate the effect of plant diversity on soil microbial abundance, community composition, and nitrogen cycling functional capacity. Using Diversity-Interactions (DI) modelling, we measured the effects of plant richness, relative abundance, and composition on soil microbial communities. We found no or weak effects of plant identity and even weaker effects of interspecific interactions on microbial abundance and function. Where differences in identity effects occurred, the plant species involved were not consistent across responses. Soil microbial community composition was significantly affected by plant species composition, and this was more strongly seen in fungal communities compared to prokaryotic communities. There were no differences in microbial community composition between L. perenne monocultures receiving a high and lower nitrogen application; however, the high nitrogen L. perenne had a different microbial community structure to some other plant communities at lower nitrogen. Overall, our study found weak effects of plant diversity on several measures of microbial diversity and function in intensively managed agricultural grasslands.