Timing and Rate of Fertilizer N Application Influence Corn Yield and Total N Uptake.

The timing and rate of fertilizer N application can influence corn (Zea mays L.) grain yield. Experiments were conducted in 2014 to compare single and split applications for differing rates of fertilizer N on an irrigated Hubbard-Mosford loamy sand complex at Becker, MN and under non-irrigated conditions on a Normania loam soil at Lamberton, MN and on a Nicollet clay loam soil at Waseca, MN. A full (100%) rate of N applied as a three-way split (before planting, at the six leaf collar (V6) corn stage, and at silking) produced greater grain yield than all other rates and timings of fertilizer N application at Becker. Conversely, the 125% N rate applied preplant produced greater yield than all other treatments at Waseca. There were no differences in grain yield due to rate or timing of fertilizer N application when N was applied at Lamberton. These results demonstrate that a three-way split-application of N can increase corn grain yield on irrigated coarse-textured soils. Enhanced understanding of site-specific soil and weather characteristics, that influence such responses could increase corn yield and N uptake while reducing the potential for N losses to the environment.