Read: more details in Agricultural Research.

Managing Forage for Best Use of Manure

Scientists at the Agricultural Research Service have uncovered ways to maximize the uptake of nutrients from animal waste by forage plants grown for hay.

Hayfields and pastures in the southeastern United States are often fertilized with animal waste such as poultry litter and swine effluent. Farmers apply these wastes because they’re effective, low-cost fertilizers. But when these nutrients accumulate in soils, they can cause environmental problems. For example, phosphorus and some forms of nitrogen move rapidly through the soil and can contaminate surface and ground-waters.

The researchers have found that more than half of all the animal waste nutrients taken up by forage plants--like annual ryegrass, red clover and bermudagrass--concentrates in their stems or runners. By maximizing stem production, growers can optimize the uptake of a nutrient such as phosphorus from the soil.

Managing the forage for hay production not only removes excess nutrients from the soil but provides the farmer with another source of income when the hay is sold off the farm. While making forage into silage also removes nutrients from the soil, the product is more difficult to transport.

The scientists found that the species of forage plant influences the levels of nutrient concentration and retention. And the amount of nutrients also increases with the age of the plant until it is fully mature.

These findings suggest that managing forage plants for growth and maturity and then harvesting them as hay for selling off-farm would maximize nutrient removal and lessen the impact that excess nutrients have on the environment. ARS plant geneticists Dennis Rowe and Gary Pederson, and colleagues conducted the studies at the agency's Waste Management and Forage Research Unit at Mississippi State, Miss.

An article describing this research in greater detail appears in the May issue of Agricultural Research, ARS’ monthly magazine, found on the web.

ARS is the U.S. Department of Agriculture’s chief scientific research agency.

Scientific contact: Gary A. Pederson, ARS Plant Genetic Resources Conservation Unit, Griffin, Ga., phone (770) 228-7254, fax (770) 229-3323, gpederson@ars-grin.gov.