Slow Release N for Enhancing Irrigated Hard Spring Wheat Protein
Brad Brown
Producing high yielding irrigated hard red spring wheat with acceptable protein has been challenging for producers despite their efforts to manage available N for protein enhancement. Both higher fertilizer N rates and split applications are used by growers but even these measures often result in protein concentrations that result in low protein price discounts, especially for furrow irrigated growers. Lacking the means provide N with the irrigation water, some growers may try to provide all the N during early vegetative growth which increases the risk of lodging and lower yields from excessive N . A single pre-plant broadcast of fertilizer N that could match or increase the effectiveness of later topdressed N (1) could reduce application costs, and (2) reduce N losses from volatilization, leaching, and immobilization (3) reduce the risks of producing high protein hard wheat under furrow irrigation.
Field trials were conducted in 2005, 2006 and 2007 at the Parma R & E Center with furrow irrigated hard red spring wheat to evaluate a preplant applied polymer coated slow release urea fertilizer (Agrium ESN) relative to conventional urea applied preplant and a split application of urea. Research reports for these trials are available as online pdf files below.
In two of three years, wheat fertilized preplant with ESN was more productive than with preplant urea. In one of two years, wheat that received preplant ESN slow release N had higher protein than wheat receiving preplant conventional urea, and in all years protein with ESN did not differ significantly from wheat receiving 60 lb N of the total urea as a late season topdress. In two of three years, preplant urea at higher rates was excessive for wheat and reduced yield. Preplant ESN slow release N was more productive than preplant N at the highest N rate presumably due to less excessive N available during early vegetative growth and increased N availability during reproductive growth.
Progress Reports
Conference Proceedings
Slow Release N for Irrigated Hard Red Spring Wheat Yield and Protein. B. D. Brown. 2008 Idaho Nutrient Management Conference, Jerome, ID.