Effects of Foliar Applied Nitrogen on Hard Red Winter Wheat Prior to Feekes 8

Abstract

Recent drought and market instability has led farmers to reduce pre-plant and mid-season nitrogen (N) applications. The objective of this project was to determine the effects of a foliar N prior to Feekes 8 (F7) in hard red winter wheat (Triticum aestivum L.), and ensuing effects on grain yield and total grain N. Studies were conducted at three locations in 2012-2013 and 2013-2014. Two rates of foliar N, 17 kg ha-1 and 34 kg ha-1 were evaluated at four dilution ratios. Nitrogen dilution ratios consisted of 1:0, 1:1, 2:1 and 3:1 parts urea ammonium nitrate (UAN, 28-0-0) to water. Two rates of a low salt (LS) N source, 17 & 34 kg ha-1, were also applied prior to Feekes 8. A pre-plant N rate was also evaluated (90 kg ha-1) to determine maximum yield potential. Foliar applications consistently improved average yields above the 0-N plot. However, they did not always reach maximum yield potential. No trend was found across all site years for any single treatment. Foliar rates were significant at one location, while the dilution ratio was significant at 3 sites. Urea ammonium nitrate proved to be a practical N source for late season applications in N deficient wheat, and based on average yields it was concluded that F7 applications are beneficial regardless of dilution.