Can Management Practices Enhance Corn Productivity in a Rye Cover Crop System?

Abstract

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.Core Ideas A cereal rye cover crop preceding corn can result in reduced grain yield. Rye cover crop did not affect corn plant population. Starter N improved early corn growth but not grain yield. Corn yield was 1.6% reduced with the rye cover crop, but tillage improved yield by 3%.