Efficient nitrogen management results in more cow milk production

Washington, May 29 (ANI): Dairy farmers can make their cows produce more milk by efficiently managing nitrogen, researchers have found.

Agricultural Research Service scientists and cooperators have come up with efficiency ratings to help dairy farmers make better use of their nitrogen in the face of escalating costs and increasing nutrient regulation.

It can be applied to prevent the waste of nitrogen in manure and urine.

ARS soil scientist J. Mark Powell at the U.S. Dairy Forage Research Center in Madison, Wis., worked with ARS agricultural engineer Clarence Rotz at the ARS Pasture Systems and Watershed Management Research Unit in University Park, Pa., and Australian colleagues to calculate nitrogen use efficiency ratings to guide dairy farmers.

The scientists found that only about 20 to 35 percent of the nitrogen fed to dairy cows is converted into milk. They also discovered that 16 to 77 percent of the nitrogen in manure or fertilizer is necessary for grass and other pasture plants. And their study showed that between 8 and 64 percent of all the nitrogen applied to typical commercial dairy farms is converted into farm products.

They determined the whole farm nitrogen use efficiency by applying the ARS-developed Integrated Farming System Model on two typical dairy farm types in Wisconsin. They used the model to quantify the effects of numbers of cows per acre and manure nitrogen credits (reducing fertilizer nitrogen applications when manure is applied) on nitrogen use, farm profitability, and pathways of nitrogen loss.

The wide ranges in nitrogen use efficiency point to the fact that there is significant room for improvement by using various practices that improve nitrogen use, profits, and the environment. Nitrogen use efficiency formulas can be used as tools to promote practices that maximize nitrogen use so that nitrogen does not leave farms to pollute waterways and ground water and negatively impact air quality.

From these tools, which are effectively a nitrogen efficiency audit, may come recommendations to dairy farmers, consultants, and policy makers. (ANI)