ISSUE 6 June 8, 2006
PROTEIN ENHANCEMENT OF SPRING WHEAT
With wheat approaching heading in some of the earliest seeded areas, the questions arise whether protein enhancement through supplemental N application is needed and how to do it. The first question is whether there will be an economic benefit to higher protein this year. The poor crop in the southern and central Great Plains usually results in higher protein in the crop . In those years when the winter wheat crop has higher protein, protein premiums are small to non-existent in this northern region. Check with a trusted local grain handler to see what they think about prospects for premiums. With N prices hovering around 30 cents/ lb N or more, the cost of N plus application would be somewhere around $15/acre. That means that the ½ % protein enhancement possible with 30 lb N/acre would have to cover at least those costs to be profitable. With 40 bu/a wheat, that means a protein premium of about 38 cents/1/2 point.
Another consideration is that many areas in the state have had temperatures over 90 degrees for at least a day, and at some locations for a series of days last week and then again this week. Those locations with less than 90 degrees have had a series of days above 80 degrees, with nights of 60 degrees or better common. These warmer temperatures may have chipped away at yield potential, so that the N applied already may be sufficient to produce higher protein without help from added N.
If the decision is made to supplement N for protein enhancement, the following recommendations have resulted in the best outcome in research trials in the region. For the most consistent results, use a foliar application, not streamer bars unless it will rain at least 1/4 inch within 24 hours of application. Do not apply the 28% with fungicides. Put the fungicide on first when the label suggests. Apply the 28% directly after flowering at the watery-ripe stage of kernel development. Apply the 28% mixed half and half by volume with water and spray during the cool of the day. Unless the day is cloudy and cool, this means towards evening. Some growers have good success with application at night, but stop early in the morning. Application made late morning when the dew is burning off has resulted in burn similar to mid-day to afternoon applications. Applications of 10 gal 28% (30 lb N/acre) has resulted in protein increases from ½ to 1%, with ½ % being the more common.
There are some slow release N products that claim higher efficiency than 28%. Although these products have less burn potential, research at NDSU has not shown higher efficiency in protein enhancement. It appears that similar rates of N need to be applied with these products to increase protein to the levels achieved with the recommended rates of 28%.
Dr. Dave Franzen
NDSU Extension Soil Specialist