Can management practices enhance corn productivity in a Rye cover crop system?

Cereal rye (Secale cereale L.) cover crops (RCC) have good potential to take up residual NO₃ between grain crops and reduce loss to surface waters. However, studies in Iowa have shown a 6% corn (Zea mays L.) yield reduction in no-till when grown following a RCC. The objective of this research was to study tillage and starter N agronomic practices that have potential to improve corn yield in a RCC system. This study was conducted at four sites from 2014–2016 with corn grown in rotation with soybean [Glycine max. (L.) Merr.]. Treatments included rye aerial broadcast into soybean before leaf drop and no RCC, tillage or no-till, and starter N fertilizer (34 kg N ha^–1) or no starter. The main fertilizer N was sidedressed. The aerial rye sowing, especially with dry fall conditions and planned RCC termination in the spring at 15–20 cm height, resulted in non-uniform RCC stand with low biomass and N content (range 6–36 kg N ha^–1). However, the profile soil NO₃–N at rye termination was decreased, approximately the same amount as the RCC aboveground N content. The V6 stage corn height and V10 stage canopy sensing indexes increased with tillage and starter. Overall, corn yield was reduced with the RCC (0.2 Mg ha^–1), tillage increased yield (3%), but starter N did not increase yield despite consistent increased early corn growth. If soil erosion potential is low, springtime tillage would be a practice to help improve corn early growth and yield in a RCC system.