Estimating the Contribution of Soil Microbial Communities to the Crop Rotation Effect.

Crop rotation is common cultural practice that has been practiced for thousands of years. This is due to the many agronomic benefits associated with crop rotation. These benefits include increased yield, decreased disease pressure and decreased nutrient amendments. While the benefits of crop rotation have been well established, the major drivers behind it remain unclear. The soil microbiome is a key component to plant health and plants can tailor the microbial community they recruit based on the composition of their root exudates. Due to this fact, the soil microbiome could be changing significantly with crop rotation and playing a key role in driving the crop rotation effect. In order to determine contribution of the microbial community to the corn-soy crop rotation effect, the bacterial and fungal richness and diversity were measured under four corn-soy rotation schemes (continuous corn, continuous soy, annual corn-soy rotation and a five-year corn-soy rotation) at Arlington Agricultural Research Center in Arlington, WI. The aim of this study was to determine how the soil microbial communities respond to different lengths of corn-soy rotation and if specific OTUs correlate with high yield. Using an Illumina 2x250 Miseq run, targeting the bacterial V4 region of the 16S rRNA and fungal ITS1-2 region of the internal transcriber spacer region, the soil communities were evaluated for beta diversity, alpha diversity and richness based on rotation scheme. This study provides growers with data on the best corn-soy rotation sequence to foster microbial communities associated with high yield.