Comparing Yields, Profitability, and Nutrient Loss of C-S-W with Conventional C-S

In the highly productive, glaciated region of Illinois, nutrient loss is mediated by the frequency and duration of tile drainage, directly contributing to surface water quality impairment. The timing of fertilizer nitrogen application to maize is critical in controlling tile nitrate loss; however, our research group has also documented significant tile nitrate loss following soybean crops. These results indicate that soil nitrogen mineralization is an important source of tile nitrogen load and that overwintering cover crops may be the best way to recouple the carbon and nitrogen cycles. This 5-year study evaluates tile nutrient loss from a conventional corn-soybean rotation versus a corn-soybean-winter wheat rotation with cereal rye following corn and double crop soybean following wheat. We also include an N rate trial in the corn phase of both rotations to compare and contrast the economic optimum N rate each year. This study demonstrates proof of concept that a more diverse rotation can greatly reduce tile nitrate loss, while maintaining yield and profitability.