Corn Response to Drainage and Fertilizer on a Poorly Drained, River Bottom Soil

Abstract

Poorly drained soils located in Missouri river bottoms have not traditionally been tile drained due to high clay content in the surface soil layers and low overall soil hydraulic conductivity. A combination of increased land and corn (Zea mays L.) grain prices along with increased variability and intensity of rainfall have stimulated interest in the region to utilize managed subsurface drainage (MD) to increase yields. The objective of the study was to determine the effect of subsurface tile drainage systems [no drainage (ND), free drainage (FD), and MD] and N fertilizer source (polymer‐coated urea [PCU] or non‐coated urea [NCU]) on corn yield in a poorly‐drained river bottom soil. Abnormally dry growing seasons in 2011 to 2013 likely limited N loss, plant N uptake, and the subsequent yield response to PCU and drainage. Applications of PCU did not impact corn yield regardless of the presence or absence of drainage. Increased corn yields with MD compared to FD were not observed over the 3‐yr study. Subsurface drainage (FD or MD) increased yields up to 13% compared to ND in 2012. Poorly‐drained river bottom soils in the Midwest typically have saturated soil conditions for an extended period of time after corn emergence regardless of whether high amounts of rainfall were received due to the low landscape position and temperature. The presence of drainage may have promoted deeper root development compared to ND and improved water use efficiency during the dry summer months which may explain the increased yield production with drainage in 2012.