Forage for Best Use of Manure
May 9, 2001
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 theyre 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
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
Agricultures chief scientific research agency.
Scientific contact: Gary A. Pederson, ARS
Resources Conservation Unit, Griffin, Ga., phone (770) 228-7254, fax (770)