Nitrogen and Crop Rotation As Drivers of Soil Microbial Community Structure.

The soil environment is a dynamic network of ecological interactions influenced by below-ground and above-ground processes. Changes in nutrient regimes, for example varying carbon substrates through rotations or enhancing nitrogen through fertilization amendments, can perturb microhabitats and drive changes in microbial community structure. Investigating these disturbance events is important for ascertaining the role of resilience, resistance, and redundancy in maize-associated microbial communities. We hypothesize that under less diverse cropping conditions (e.g. continuous corn), nitrogen fertilization will play a more significant role in shaping microbial community structure due to the reduced intensity of disturbance. Sampling from a long-term field site with established crop rotations and nitrogen fertilization treatments, we characterized broad microbial classes with fatty acid methyl ester (FAME) profiling and conducted 16S amplicon sequencing. Preliminary results suggest that crop rotation is a major driver of microbial community structure and that nitrogen is a more important contributor to community composition under less diverse cropping rotations.