Project Number: 1245-12630-005-20
Project Type: Specific Cooperative Agreement

Start Date: Sep 01, 2012
End Date: Aug 31, 2015

Objective:
To use labeled fertilizer nitrogen (N) applied to corn to quantify the ability of a winter wheat commodity cover crop (wheat without fall N fertilizer) vs. a traditional winter wheat crop (wheat with fall fertilizer N) to scavenge corn residual nitrate N, and to compare the fertilizer N uptake efficiencies of two modern corn hybrids, one with and one without multiple pest-resistant genomics.

Approach:
Two field-plot experiments will be conducted, each with a two year corn-wheat rotation. The corn treatments will be six rates of 15N labeled fertilizer on each of two corn hybrids, one with and one without multiple pest-resistant genomics. The corn fertilizer N uptake efficiencies of each hybrid will be determined by total 15N uptake at physiologic maturity, as well as grain 15N removal. After corn harvest, soil samples will be taken to determine the quantity of labeled N remaining in the root zone. Fall winter wheat will be established on all plots with half the plots receiving no fall fertilizer-N (commodity wheat cover crop), and the other half receiving the recommended rate of unlabeled fertilizer-N (traditional winter wheat). All wheat will be grown to maturity with grain and straw samples collected for determining the total recovery of the fall residual-15N by each winter wheat system. These data will provide estimates of the N uptake efficiency of two modern corn hybrids, and the ability of a wheat commodity cover crop vs. a traditional wheat crop to recycle corn residual N in this grain-cropping system.