Premium
Influence of Late‐Season Foliar Nitrogen Applications on Yield and Grain Nitrogen in Winter Wheat
Author(s) -
Woolfolk Curt W.,
Raun William R.,
Johnson Gordon V.,
Thomason Wade E.,
Mullen Robert W.,
Wynn Kathie J.,
Freeman Kyle W.
Publication year - 2002
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2002.4290
Subject(s) - straw , nitrogen , agronomy , ammonium sulfate , urea , winter wheat , ammonium nitrate , grain yield , yield (engineering) , growing season , ammonium , chemistry , wheat grain , biology , materials science , organic chemistry , chromatography , metallurgy
Increasing grain protein in new higher‐yielding cereal grains has recently received added attention due to protein premiums paid to farmers. Hard red winter wheat ( Triticum aestivum L.) studies were conducted at two locations in Oklahoma in 1997–1998, 1998–1999, and 1999–2000 to evaluate the effects of late‐season foliar N applications on grain yield, total grain N, straw yield, and total straw N. Foliar applications of N were made at two different times (pre‐ and postflowering) using urea ammonium nitrate (UAN) at rates of 0, 11, 22, 34, and 45 kg N ha −1 . Ammonium sulfate [(NH 4 ) 2 SO 4 ] was also applied at a single rate of 22 kg N ha −1 both pre‐ and postflowering. A significant linear increase in total grain N was observed for postflowering applications using UAN in five of six site‐years. In four out of the six site‐years, a significant linear increase was observed for preflowering applications of UAN. No consistent increases or decreases from foliar N applications were observed for grain yield, straw yield, or straw N. Over years and locations, UAN applied preflowering and postflowering at 34 kg N ha −1 increased total grain N over that of the check (no foliar N applied) by 2.7 and 2.4 g kg −1 , respectively. Late‐season foliar N applications before or immediately following flowering may significantly enhance grain N content and, thus, percent protein in winter wheat.