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Posted 25 March 2011. Crop Management. Nitrogen and Fungicide Applications for Wheat Fields Source: University of Illinois Press Release. aces.illinois.edu Urbana-Champaign, Illinois (February 23, 2011)--The dry fall last year was ideal for growers to get wheat seeded. We have not had such good opportunities for several years; and, as a result, we have seen an increase is the amount of wheat acres sown. While a number of producers have reduced wheat acres due to problems with diseases reducing yields, we do have new fungicides available today that can help reduce the catastrophic losses that head scab has caused in the past.
The University of Illinois also has new nitrogen rate recommendations available that more closely examine the economics of wheat yield and nitrogen price. This is similar to our corn nitrogen rate calculator which bases nitrogen applications on the economics of nitrogen rate return. Based upon current prices (urea price of $500 per ton and a wheat price of $8 per bushel) the optimum rate of nitrogen for wheat would be anywhere from 70 to 150 pounds per acre. The factor to determine the appropriate rate is soil organic matter. On low organic matter soils (less than 2 percent) the optimal nitrogen rate is 150 pounds. On medium OM soils (2 to 4 percent) the optimum rate is 100 to 120 pounds. On high OM soils, the optimum nitrogen rate is 70 to 90 pounds. Most folks would probably have a difficult time with the thought of applying 150 pounds of nitrogen to a wheat crop, but based upon recent research, that is the economic optimum. If nothing else, this should convince you to at least increase your rate to take advantage of the high wheat prices being offered now. You may not want to bite the bullet and apply the 150-pound rate, but you should at least consider increasing your normal rate. You might also consider splitting the rate to two times—spring green up and again just before stem elongation. This is a more sustainable system that optimizes nitrogen application to coincide with plant uptake. In doing this you can reduce your nitrogen rate by 10 percent. Research has also proven that nitrogen form (dry or liquid) does not seem to matter much. Of course, if you are going to go for high wheat yields, you need to seriously consider fungicide applications to protect the plant. Fungal diseases such as leaf blotch and head scab have severely reduced wheat yields in the past. Scout the plant for disease lesions, and apply fungicides based upon those findings. For control of leaf blights, rust, and powdery mildew, Ohio State recommends application when there are as little as 1 to 2 lesions or 8 to 10 pustules (depending upon which specific disease) on the second leaf below the flag leaf. Never use the strobilurin fungicides (Quadris, Headline) at heading. There are several fungicides for control of head scab, including Proline, Prosaro, and Caramba. Research has proven these products provide good control of this devastating disease in addition to the fungal diseases listed above. The use of the scab predictor website (www.wheatscab.psu.edu) and these two fungicides can really help reduce head scab losses. Remember scab can only infect during bloom. So scout your field at bloom and utilize the scab predictor website to help determine if or when to apply a preventative fungicide based upon conditions favorable for scab to develop. Contact: |
