Effects of crop diversity on plant-soil-microbial interactions

Ariane L Peralta and Yanmei Su
Department of Biology, East Carolina University

Presented at the All Scientists Meeting (2015-04-15 to 2015-04-16 )

Manipulation of agricultural management can have lasting impacts on microbial community structure and function. Consequent changes in biotic (i.e., plant inputs) and abiotic factors (i.e., nutrient cycling) due to agricultural management directly influence soil microbial community structure and function in contemporary ecosystems. The goal of this study was to investigate the impact of long-term crop diversity on soil microbial diversity. We collected soil samples from the Biodiversity Gradient Experiment at Kellogg Biological Station LTER. At this long-term experiment, crop diversity is manipulated, ranging from monoculture to a five species crop rotation. We sampled 7 treatments all in the corn phase of the rotation along the biodiversity gradient and a spring fallow treatment (November 2012). Using molecular techniques, we examined the influence of crop diversity on total bacterial community composition (16S rRNA amplicon sequencing) and a subset of bacteria capable of producing antifungal compound 2,4-diacetylphloroglucinol (phlD gene fingerprint analysis). We also evaluated the relationship between microbial community composition and plant inputs across the crop diversity gradient. We demonstrate that crop diversity treatment significantly influenced bacterial community composition. In addition, total carbon was the only soil factor to significantly explain bacterial community variation. Based on variance partitioning of plant effects due cover crop, weed, or crop inputs on microbial community composition, we found that cover crop biomass significantly contributed to variation in bacterial community composition. Initial research findings indicated that crop diversity influenced bacterial community composition. Plants and microbes drive nutrient cycling in this long-term crop diversity since no other synthetic or organic amendments are applied. Differences in plant contributions to soil organic matter pools can be a possible mechanism driving shifts in microbial community patterns. Further work examining long-term nutrient impacts on microbial carbon usage is ongoing.

Back to meeting | Show |