9/13/2013 at 12:00 a.m.
From the University of Arkansas Division of Agriculture:
FAYETTEVILLE — When bermudagrass goes dormant in the cold, winter annual legumes can help span the forage gap between October and May, said Dirk Philipp, assistant professor for the University of Arkansas System Division of Agriculture.
“Winter annual legumes such as clover, are a good way of providing forage in spring and add plant material to the soil,” Philipp said.
With planting time in the southeastern U.S. ranging from the middle of September to the middle of October, now is the time to make decisions. In Arkansas, planting times range from Oct. 1 for the northern part of the state to Oct. 15 for the southern part of the state.
If the main goal for winter legumes is grazing, growers should know that “initial grazing height varies with species, but plants should reach at least 6-8 inches before grazing begins,” he said, adding that pastures may “be rotationally stocked if grazing twice during spring is the goal.”
The main advantage is to provide grazing and recycle accumulated plant nutrients back to the soil, Philipp said. “This effect may be minor in the short-term. If grazing is the goal, then focus should be on optimizing forage use through appropriate stocking methods.”
Legumes have been used as “green manure” for a very long time, and this practice still continues today in many areas of the world, he said.
“Mostly, legumes need to be incorporated into the soil to receive benefit from added plant biomass, organic material breakdown, and slow release of nutrients,” Philipp said. “Since incorporation will damage the perennial warm-season grasses, this option may have to be reserved for areas where the annual legume is followed by a summer annual grass, such as pearl millet.”
“The advantage of this approach is that plant biomass is recycled in a broad manner and not just in a localized fashion if biomass passes through animals and is deposited,” he said.
Maximizing the benefits of grazing and simultaneous nutrient recycling requires some planning and management efforts.
Legumes can be either overseeded into existing perennial grass pastures or planted in separated areas that may increase higher establishment success using somewhat higher seeding rates.
Philipp said that animals can be rotated between legume areas and perennial grasses to avoid problems with a legume-only diet, which is rich in protein. Rotating animals between paddocks has the added benefit of “transferring nutrients away from the legume areas to the perennial grass areas.”
Grazing tall fescue, a cool-season perennial grass, can begin in March or April, which coincides with the graze-ability of annual legumes.
While the dietary benefits may be short term, over the long term, the benefit will tip toward a longer-term increase in soil nutrients.
“When using annual legumes, success of establishment can vary over the years and producers may have to experiment with different species and/or varieties to synchronize forage needs by animals and forage growth as much as possible,” Philipp said.
For more information about establishing forage annual legumes, contact your county extension office or visit or download FSA 3137 ‘Annual and Perennial Forage Clovers for Arkansas.'