Yield and protein response of wheat cultivars to polymer-coated urea and urea.

摘要

Discount payments associated with low grain protein concentration in hard red spring wheat (HRSW, Triticum aestivum L.) in recent years has increased interest for using controlled-release N fertilizers to increase protein concentration while maintaining optimal grain yields. Field experiments were conducted during 6 site-years in Minnesota from 2007 to 2009 to examine effects of a polymer-coated urea (PCU, Environmentally Smart Nitrogen [ESN], Agrium Inc., Calgary, AB, Canada) and non-coated urea on grain yields and protein concentrations of two HRSW cultivars, Alsen and Knudson, that vary in grain yield and protein concentration potentials. Polymer-coated urea and urea were applied in spring at six rates that supplied 0 to 110 kg N ha-1 in 2007 and 0 to 168 kg N ha-1 in 2008 and 2009. Because of genetic differences, Knudson produced greater grain yield than Alsen in environments (site-years), which were cooler and drier early in the growing season and the yield differences between the two cultivars increased with increasing N rates. In the same environment, PCU decreased grain yield compared with urea, which could be related to a reduced N release early in the growing season. Compared with urea, higher N (at Zadoks scale 85) and protein concentrations (at Zadoks scale 92) with PCU were observed due to increased N availability later during the growing season. To increase wheat protein concentrations from using PCU, future studies should evaluate different mixtures of PCU and urea.