Bacteria: Contour prairie strips alter soil microbial communities and functioning both below the prairie strip and in adjacent cropland

Prairie strips are narrow strips of native, perennial vegetation integrated within cropped fields. Prairie strips provide disproportional benefits for water quality and biodiversity. However, the impact of prairie strips on soil microbial communities and function, both underneath the prairie strips and in the adjacent cropland, is not known. We assessed the effect of restoring native perennial vegetation on soil C and N, potential enzyme activities, and microbial community composition in the soil directly underneath and adjacent to 12 year old prairie strips integrated within row crop fields. We found that prairie strips consistently increased microbial biomass carbon, and altered PEA, but this effect depended on the year. Generally, prairie strips increased hydrolase and decreased oxidoreductase PEA. Prairie strips also changed the soil microbial community directly under prairie vegetation, and, contrary to the expectation that greater plant diversity leads to greater soil microbial diversity, prairie strips reduced bacterial and fungal diversity. The prairie strip effect on surrounding cropland soils depended on year and metric, but it was strong when it occurred and was typically independent of distance from the prairie strip. Prairie strips increased PEA in adjacent soils and shifted bacterial and fungal beta diversity, but neither showed patterns with distance from the prairie strip, indicating that prairie strips cause field scale shifts in soil biota and functioning, but these effects are not mediated by proximity to the prairie strip. Understanding the mechanisms underlying prairie strips impact on soil biota, both underneath and adjacent to the prairie, is key to optimize their agroecosystem benefits.