Maximizing Winter Annual Forage Yield

By Kendra Phipps

With the beginning of March comes the onset of Spring fever, and winter annual forage growth along with it. If you’re growing winter annuals like wheat, oats, rye, or triticale for forage, the best way to maximize your forage yield is to top-dress, or apply nitrogen fertilizer, during the Spring following green-up of the forage. But, how can you know you’re hitting the sweet spot of maximizing yield and without sacrificing profit?

Before top-dressing your winter annuals, consider the following:

• Was fertilizer applied in the fall? Top-dressing should be used as part of split fertilizer application to maximize nitrogen (N) usage for the plant. For example, if the goal is to apply 100lbs/ac N, it is likely that nitrogen use will be maximized by splitting the application to 40lbs/ac of N at planting, and 60lbs/ac of N at green-up during in the Spring.

• What nitrogen fertilizers are available and economical? Many times, the best fertilizer is a fertilizer you can get and apply in a timely manner. But, for top-dressing, don’t forget that some nitrogen sources can damage growing plants. Anhydrous ammonia can damage plant root systems, while liquid nitrogen (urea ammonium nitrate (UAN)) can cause foliar damage when applied during hot weather. Granular urea can also volatilize and become unavailable for plant use during hot weather.

• The recommended amount of nitrogen fertilizer will vary based on several factors. Once again, the best amount of fertilizer to apply depends on fertilization history, yield goals, and economic factors. Generally, the goal is to apply 40-60lbs N/ac.

• Don’t forget to calculate the exact amount of N being applied. For example, if you choose to apply 150lbs/ac of UAN, which is labeled as 32-0-0, the math would come out like this:

• 32% nitrogen * 150lbs = 48lbs N/ac.