A new agricultural research project is looking for ways to prevent phosphorus in manure from running off into the Bosque and Leon Watersheds. The challenge is to do so without sinking the region's dairy industry.

Funded by $800,000 in grant monies from the U.S. Department of Agriculture and the Environmental Protection Agency, the project pools the efforts of experts from the Texas Agricultural Experiment Station, Texas Cooperative Extension and Tarleton State University.

At stake is not only preserving water quality in Central Texas, but reinforcing an industry crucial to the central Texas economy, said Dr. Barry Lambert.

"The city of Waco, downstream from the dairies on the Bosque River watershed, has placed much of the blame for (Lake) Waco water quality issues on the dairy industry in orth-Central Texas," said Lambert, dairy nutritionist with a joint appointment with the Experiment Station and Tarleton State.

The issue centers not on the manure itself, but primarily concerns phosphorus, a component of manure.

The average dairy cow excretes about 40 pounds of phosphorus per year as manure. Phosphorus, when in the right proportion to other compounds such as nitrogen and potassium, is an essential crop nutrient. Dairy farms typically spread the manure, either composted or as a slurry from catch lagoons, on crops as fertilizer.

The typical crop is some sort of forage, which uses 1 pound of phosphorus for every 4 pounds of nitrogen. The forage is a method of recycling manure, and if the proportions of phosphorus to nitrogen were correct, it would be an efficient, environmentally friendly system. "The majority of phosphorus leaves the dairy farm as either milk or manure," Lambert said. "Phosphorus is an essential nutrient for humans, so the milk part is good."

But dairy manure is high in phosphorus, having about 1 pound of phosphorus to every 2 pounds of nitrogen. It's this leftover ph
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Contact: Robert Burns
rd-burns@tamu.edu
903 834-6191
Texas A&M University - Agricultural Communications
2-Mar-2005