The economic incentive to increase protein in spring wheat to avoid discounts or realize a greater protein premium so far this season is low. It is impossible to predict with certainty what will actually happen when the combines take the grain off the fields in North Dakota, but if the present pricing structure is any indication of the future, the benefit from a post-anthesis application of N does not exist so far this season.
The ‘recipe’ for consistent protein increase of at least 0.5% to about 1% is to apply 30 lb N/acre as UAN (10 gal/acre of UAN) with 10 gal/acre water, using flat fan nozzles immediately after anthesis (flowering) while the wheat berries are still in the watery ripe stage. Apply in the cool of the day (from very early in the morning until about 10 AM on hot days). The cost of this application is probably around $20 per acre or more. Some growers and suppliers have produced a solution of urea and water alone and applied it at a 30 lb N/acre rate and this has also been successful. The cost might be a little lower than using UAN.
Avoid the trap of using a low rate of a slow-release N fertilizer that claims to be several times more efficient than UAN to increase wheat protein. These types of products have been extensively researched at NDSU by several independent researchers and the claims for higher efficiency are unfounded. See my website and the white paper regarding slow-release N fertilizers for more information.
According to some elevator websites I scanned today in western North Dakota, the protein premium going from 13% to 14% is only about 15 cents per bushel. With 50 bu/acre wheat, that is only about $7.50 per acre increase. Growers would lose over $10/acre within the present price structure if they apply post-anthesis N this year. However, if N losses were high this season and grain yields are correspondingly high, the presence of an overwhelming quantity of lower protein wheat might result in higher protein premiums and higher low-protein dockage at harvest time. This happened within the past 5 years when high rainfall in western ND resulted in protein content commonly between 9-12 percent.
The decision to apply or not apply post-anthesis N is purely a grower marketing decision. The ‘recipe’ for increasing protein is well established. Unfortunately, the real economics behind the decision to increase protein relies on grower intuition of future events beyond their control.