Yield for Injected and Banded Nitrogen Fertilization for No-Tillage Winter Wheat.

Wheat acreage produced using no-tillage has increased across Virginia over the last 10 years resulting in a need for refinement of fertilization practices. We initiated a study on loam and sandy loam soils to test the utility of various N treatment application methods and to find the corresponding N rate for each practice that produced highest yields. Nitrogen application methods included surface-broadcast, surface-banded (38 and 76 cm bands), and subsurface-banded applications (38 and 76 cm bands) of urea-ammonium nitrate (300 g N kg^-1) at four different N rates (45, 90, 135, and 180 kg N ha^-1). Three no-fertilizer controls were included. Two of the no-fertilizer controls had the subsurface applicator ran across the plots at 38 and 76 cm spacing to test for plant damage from the no-tillage coulters. Nitrogen treatments were made in the spring with 50% of the N applied at Zadok’s growth stage 25 and the remaining N applied at Zadok’s growth stage 30. Wheat grain yield was used to compare N treatments. At the loam soil location, wheat yield was highest when 135 kg N ha^-1 was used (4368, 5330 and 7392 kg grain ha^-1 for 2009, 2010 and 2011 respectively); averaged across application method. For application method, 38 cm surface banded applications had superior yields compared to other treatments and averaged 4704 kg grain ha^-1 in 2009; averaged over N rate. In 2010 and 2011, all N application methods were equal and averaged 5013 and 7526 kg grain ha^-1. Overall, alternative N fertilization practices may increase yield in certain years and may not harm yield in other years.