Corn Yield Response to Managed Drainage and Polymer‐Coated Urea

Abstract

With poorly‐drained claypan soils in the midwestern United States, it is common to have wet soil conditions in the spring and dry soil conditions in the summer. Management practices that can improve or mitigate the effects of excessive wet and dry soil conditions are essential to obtain maximum corn (Zea mays L.) yield potential. The objective of the 4‐yr study was to determine if subsurface drainage (free drainage [FD] or managed drainage [MD]) with polymer‐coated urea (PCU) could increase corn yield compared to an application of non‐coated urea (NCU) without drainage (ND) in a claypan soil. Corn grain yields were low over the 4‐yr study due to extreme wet conditions in 2010 that delayed planting and mild to extreme summer drought conditions in 2011 to 2013. Averaged over 2010 to 2013, corn grain yields ranged from 4.76 to 5.75 Mg ha−1. Averaged over 2010 to 2013, the presence of drainage (FD or MD) increased corn yield (15–21%) compared to ND when NCU was applied. In the absence of drainage, PCU increased corn grain yields 20% compared to NCU, which indicated that PCU mitigated the high N loss potential in a wet soil environment. Managed drainage averaged a 4% increase in corn yield compared to FD. Corn yield increases with drainage compared to ND were limited over the 4 yr of this research; however, greater corn yield benefits from drainage of claypan soils might occur in years with greater overall yield potential.