Extensive research in Alabama on wheat fertilization has shown there’s no “one size fits all” nitrogen recommendation, with varying rates and timing depending on your soil type and location in the state, says Kip Balkcom, research agronomist with the National Soil Dynamics Laboratory in Auburn, Ala.

The research began in north Alabama’s Tennessee Valley where many growers were shifting to more intensive wheat production practices, said Balkcom, speaking at a recent meeting of crop consultants in Auburn.

“Growers were trying to maximize their wheat yields with different management practices,” says Balkcom.

“They were planting into existing crop residue, eliminating that one trip across the field. They also were planting higher seeding rates with higher nitrogen levels, so people were concerned. We evaluated nitrogen rates and timing across different production systems.”

Research was conducted for 12 site-years, from one end of Alabama to the other, he says, and with varying nitrogen rates.

“We had three rates of nitrogen, using 60, 90 and 120 pounds of nitrogen per acre, but we applied it at different times and different splits. We chose 20 pounds at fall because that is the current Auburn University recommendation.

“If you put on too much nitrogen in the fall, there will be excess growth, increasing the potential for winter kill,” says Balkcom.

Wheat, like corn grain, requires about 1 to 1.5 pounds total nitrogen per bushel of anticipated yield, he says. Because of its transient nature in the environment, nitrogen fertilization of wheat is the most difficult nutrient to manage, but also one of the most critical because it is an essential component of protein.

Nitrogen produces green, leafy growth, and supplying adequate nitrogen in the fall is necessary for good plant establishment. Once the weather becomes cold in December, wheat makes very little green, leafy growth until the weather warms in late winter.

“Excess nitrogen applied in the late fall is a waste of an expensive resource and can cut into profits. It also could be leached from the soil by winter rainfall and could be unavailable in the early spring when the crop needs it for rapid growth.”