North Dakota State University (NDSU) Extension has nitrogen (N) calculators for sunflower, spring wheat/durum and corn N recommendations. The calculators are available on the web or as a phone app to derive the most profitable N rate for these crops over a range of crop prices and N costs.
“At the time they were produced, the price ranges were greater than prices of commodities and fertilizers,” says Dave Franzen, NDSU Extension soil specialist. “Lately, fertilizer N costs have risen to values greater than those provided as options in the published calculators.”
“Sunflower contracts, particularly for confections, is now greater than the maximum value of 30 cents per pound of sunflower provided as an option in the sunflower calculator,” says Franzen. “Although the calculators are now under revision to accommodate seamlessly for these higher prices and costs, the calculators can still be used by dividing the grain by the seed costs and the fertilizer prices by two.”
For example, a sunflower farmer has a contract for 40 cents per pound for confection sunflowers, and N costs this spring are anticipated to be $1.20 per pound. The calculator as written does not allow for those values. However, the rate of N recommended for 20 cents per pound confection sunflower and $0.60 per pound N is the same rate recommended for 40 cent per pound sunflower and $1.20 per pound N.
“So for now, if N costs are greater than $1 per pound N and commodity prices are greater than those provided by the calculator, divide each value, both N cost and grain/seed cost, by two,” says Franzen. “Then apply those values to the calculator to derive the correct N recommendation.”
The web-based calculators can be found online at:
Spring wheat/durum - www.ndsu.edu/pubweb/soils/wheat/
Sunflower - www.ndsu.edu/pubweb/soils/sunflower/
All three calculators are available as phone apps for iOS and Android by going to the app store and searching for North Dakota N calculator. It is free to download.