“The wet year has prevented topdress nitrogen applications in the southwestern portion of the state, and in many areas of Oklahoma, much of the crop is late-sown and has not even tillered yet,” said Jeff Edwards, Oklahoma State University Cooperative Extension small grains specialist. “It will probably be mid-March before all varieties have reached first hollow stem.”

Normally, Oklahoma producers can add a couple of tillers over the winter months. That did not happen this winter.

“We have a significant amount of acreage out there with only one main tiller,” Edwards said. “If we ease into spring, there might be an opportunity to still add a few tillers.”

The biggest concern is the lack of topdress nitrogen that has been applied. The delayed wheat development means that the nitrogen application window has been extended a little for some producers; however, the window is closing rapidly.

Research indicates if wheat is not under extreme nitrogen deficiency or suffering from significant stand loss, then it can be completely recovered if topdressing is applied by first hollow stem.

“Yes, yield loss due to nitrogen deficiency can be recovered, and there is even data that shows yield can be recovered after first hollow stem as well,” said Brian Arnall, OSU assistant professor of nutrient precision management. “However, keep in mind that the closer the wheat is to flag leaf, the more nitrogen will be converted to protein in the grain and not yield.”

Of course, that leads to a key question for producers: Will applying a few gallons of nitrogen now help? The short answer: It depends on the amount of nitrogen being applied and the applicable cost to a producer’s operation. As always, there has to be some level of product cost analysis and estimated return in terms of yield.

“From the reports I have heard, pilots are able to put on 7 gallons of UAN Solution 32 (32-0-0),” Arnall said. “With this application, there could be an increase in yield of approximately 12 bushels, assuming the nitrogen is limiting and nitrogen-use efficiency is about 70 percent. At $4 per bushel, this would result in an increase of $48 per acre for a nitrogen investment of approximately $13.30 per application.”

Additionally, some producers may be considering non-traditional fertilizer sources. Most of the products on the market – UAN included – will have an average of 3 pounds nitrogen per gallon. Wheat contains about 1.29 pounds nitrogen per bushel.

“Even if we assume the fertilizer is 100 percent efficiency and not one drop is wasted, neither being very likely, the best case scenario is a grain yield increase of 2.35 bushels per gallon,” Arnall said.

Using the above example at a grain price of $4 per bushel, the breakeven for the cost of materials plus application has to be less than $9.40 per acre for a 1-gallon-per-acre rate and $18.80 per acre at a 2-gallons-per-acre rate. If a wheat price of $3.50 per bushel is used, then the maximum allowable costs fall to $8.23 and $16.45, respectively.

“While some reports have shown differences in response to nitrogen products, no OSU research has indicated a significant difference between the use of specialty fertilizers and UAN on winter wheat,” Arnall said.

Another management consideration to ponder is the fact that many herbicides can temporarily stunt wheat. This is especially true with applications made during cold temperatures or when conditions for wheat growth are poor.

“If herbicides are being mixed with a topdress application to very small wheat, it might be worthwhile to delay the applications until the wheat has a few tillers,” Edwards said. “This can be a bit tricky because the small wheat will be less competitive than larger wheat and will definitely need the herbicide’s help in holding back weeds.”