Cover Crops: One Key to Reducing Nutrients to Bay

November 2006 -- It's no secret that agricultural runoff in the Bay watershed contributes a significant amount of nitrogen and phosphorous to Bay waters. Excessive amounts of these nutrients spur harmful algal blooms that deplete dissolved oxygen levels, block out sunlight needed for bay grasses and, in some cases, produce toxic chemicals that can cause fish kills.

Farmers have been using cover crops as one way to reduce the amount of nutrients that end up in the Bay. Cover crops, which are planted in the fall after the autumn harvest, usually consist of cereal grains like wheat, rye and barley that continue to grow during the winter.

Once established, cover crops absorb excess nutrients in the soil and reduce erosion from rain, snow and wind. For every acre of farmland planted with cover crops, an estimated 6.2 pounds of nitrogen and nearly one-quarter of a pound of phosphorous is prevented from reaching our waterways, according to Bay scientists.

Enrollment in cover crop programs has risen steadily over the past several years, showing farmers' support of the initiative. Besides for the notable benefits to Bay health, cover crops also help farmers by retaining nutrients and increasing organic matter in the soil. They also help block out noxious weeds and can inhibit weed seeds from germinating.

State and federal Bay Program partners have recognized the importance of making cover crop programs available for farmers and are expanding existing programs and developing new ones to meet the increased demand. For example, Maryland has more than doubled its funding for cover crop programs to a record $8 million and 290,000 acres.

Runoff from farmland is one of many factors that contribute to high amounts of nutrients and low dissolved oxygen levels in the Bay. Increased use of cover crops each winter is one way to lessen the human environmental footprint on the Bay and support the restoration of a healthy, balanced Bay ecosystem.