Evaluating Drill Interseeded Cover Crop Establishment and Nitrogen Impact in Irrigated Corn

The adoption of cover crops as a strategy to improve soil health and cropping systems sustainability is on the rise in the United States. PRE herbicides with soil residual activity are widely applied in corn production systems to prevent early season weed development, crop-weed competition, and yield loss. When preemergence herbicides are applied in the field, the active ingredients remain in the soil rhizosphere for a period of time, killing weed seedlings as they emerge. However, PRE herbicides can also impact the establishment of interseeded cover crops. Greenhouse bioassay was conducted to evaluate the preemergence herbicide carry-over potential to interseeded cover crops. On-farm research was conducted to evaluate nitrogen uptake by interseeded cover crops that could potentially decrease nitrogen losses. The objectives of these studies were: (1) to elucidate the impact of corn PRE herbicides on CC establishment; (2) to identify the ideal time to interseed cover crops following herbicide application; and (3) to evaluate the effect of cover crops on nitrogen uptake, including corn-N, cover crop-N, and soil nitrate in different depths. Advisor: Christopher A. Procto