ESN Is The Smart Nitrogen For Montana Winter Wheat
Source: Montana State Univ. at Mocassin, MT. Yields are means of two years. Nitrogen rate of 82 lbs N/acre is MSU recommended rate as determined by yield goal of 40 bu/acre and estimated N mineralization of 30 lbs N/acre. Net return calculation is based on 4 bu/acre yield difference, wheat price of $6/bu, and ESN-urea price difference of $0.20/lb N.
ESN can be an effective tool for nitrogen (N) management in no-till winter wheat in the Northern Great Plains. This Montana State University study demonstrated that ESN, broadcast either in fall or spring can out-perform conventional urea. ESN, urea, and different blends of ESN and urea were broadcast either in the fall at seeding (late Sept –early Oct) or in the spring at “green-up” (early April).
Optimum ESN blends in both fall and spring produced greater yields than urea applied at the same time.
A blend comprised of 75% ESN produced the greatest yields with fall application. For spring application, 50% ESN blend performed best, indicating a greater need for immediately available N in spring.
The greatest yield differences were observed in 2013. In 2013, fall application of a 75% ESN blend out-yielded fall urea by almost 7 bu/acre and spring application of the 50% ESN blend out-yielded spring urea by 8 bu/acre.
Low yields with spring broadcast urea, particularly spring of 2013, indicate potential ammonia volatilization losses from this treatment.
Based on average yield difference between best ESN treatment and urea, appropriate ESN blends for the time of application increase grower net return by about $12/acre for the fall-applied 75% blend and about $16/acre for the spring-applied 50% ESN blend.
