Comparison of Nitrogen Sources for Spring Wheat Production.

There is a growing interest in new fertilizer technologies among Montana growers, dealers and crop advisors.  Environmentally Smart Nitrogen (ESN) is a relatively new form of polymer-coated nitrogen (N) fertilizer being marketed by Agrium Advanced Technologies as a slow-release material. The company claims that higher yields can be obtained using ESN compared to conventional urea. Research is needed to test the efficacy of ESN in comparison to urea for wheat production in Montana. The objectives of this study are: 1) to evaluate ESN as a N fertilizer source for spring wheat production in Montana in comparison to conventional urea, and 2) to evaluate nitrogen use efficiency, and grain yield and protein response to these two fertilizer materials, alone and in combination. This study has been funded by Montana Fertilizer Tax Advisory Committee and initiated in 2011, and continued in 2012. Field trials were conducted at two dryland sites (Western Triangle Agricultural Research Center in Conrad, MT and in a cooperating producer’s field – Jack Patton (Choteau County, MT) and one irrigated site in Montana (Western Agricultural Research Center in Corvallis, MT). Hard red spring wheat plots were treated with one of three sources of preplant N: urea, ESN, and a 50/50 mix of urea and ESN.  These materials were applied in a factorial combination with four rates of preplant N: 0, 56, 112, and 168 kg N ha-1.  Wheat canopy reflectance was measured in each plot with the Greenseeker optical sensor as a means of assessing N status of the crop, along with total-N analysis of plant tissue. The effect of N sources and rates on spring wheat grain yield, grain protein content, N uptake and NUE were evaluated. The response of spring wheat to the N sources and their rate of application will result in the development of producer recommendations, and will enable producers to make an assessment of cost effectiveness for these materials.