Proposed national standard for phosphorus derailed by critics

Last summer, U.S. Department of Agriculture officials floated a nationwide standard to limit the amount of phosphorus farmers could apply to fields. But by December, they had pulled it back in the face of stiff opposition from a group of agriculture scientists.

Their decision disappointed many of the scientists and advocates working on Chesapeake Bay restoration. The short-lived proposal and the hot debate it generated also illuminates the complexity of establishing an agriculture pollution-control policy to protect the nation’s waters.

The proposal to have a single, national guideline for phosphorus application was part of an overhaul of the USDA’s National Resource Conservation Service’s nutrient management guidelines. The overhaul aimed to find a long-term, sustainable approach to guide the application of manure and synthetic fertilizer for both maximum crop growth and water protection.

It would have phased in an upper limit for the amount of phosphorus in soil. Once a soil test showed the phosphorus had reached that amount, farmers would have been discouraged from applying more. The proposed upper limit was 200 parts per million, a number believed to represent a point at or beyond which phosphorus begins to leave the field by dissolving in rain runoff or leaching into groundwater.

Bay Journal