There are several tools small grain producers can use to gauge the nitrogen use efficiency of their crop and achieve a savings in production costs, said a Texas Cooperative Extension small grains specialist.
“When we look at production inputs, we need to put them in two categories,” said Gaylon Morgan, Extension agronomist based at College Station. Morgan spoke at the recent Big Country Wheat Conference in Abilene, Texas. “There are yield-building inputs and yield-preserving inputs.
“Nitrogen fertilizer could fall into both categories, but we chiefly use and manage it as a yield-builder. More important is nitrogen use efficiency.”
Wheat has an average nitrogen use efficiency of 33 percent, he said. In other words, about 33 percent of applied nitrogen is used by the plant to produce grain. The United States consumes about 7.3 million pounds of nitrogen fertilizer annually.
“So if we can improve our nitrogen use efficiency, we could achieve a potentially significant savings in nitrogen costs,” Morgan said. “But how do we do that ... what tools do we need?”
Producers who grow wheat, for example, should rely on soil tests to gauge actual available nitrogen for a crop and consider their crop’s realistic yield potential before applying nitrogen, he said. Soil test results matched to yield potential and the producer’s yield goal can help ensure that nitrogen is applied according to crop need and not prevailing tradition.
“Our current thinking and our current recommendation for nitrogen fertilizer is 2 pounds per acre for each bushel in your yield goal,” Morgan said. “Breeders are working to produce new varieties with higher nitrogen-use efficiency. Even so, we can do a better job with the genetics available today.
“We can better assess the crop’s true nitrogen need and time the application of fertilizer to coincide with critical growth times.”
Winter wheat, for example, needs little nitrogen in the fall. Producers who want to guarantee nitrogen availability for wheat roots should assess their crop’s nitrogen need in late winter or early spring ... possibly in February, he said.
“If you time nitrogen application to coincide with wheat’s late winter and early spring growth, you can determine the needs of the wheat crop and probably use a lower fertilizer rate while achieving the same or higher yields that a higher fertilizer rate will provide,” Morgan said. “This spring top-dress application allows you to assess the crop’s yield potential and match the nitrogen fertilizer rate to the yield potential.”