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ROMANCING THE VELVET BEAN -- OLD FLAME OF SOUTHERN FARMERS MAY MAKE
A COMEBACK
AUBURN, Ala.__-- An old romance between southeastern farmers and velvet
beans may soon be rekindled, thanks to research underway at Auburn University.
Rodrigo Rodriguez-Kabana, professor of plant pathology in Auburn's College
of Agriculture, has been exploring the use of velvet bean as a nematode
control for Alabama's cash crops. His research has shown that velvet
beans are highly effective, natural nematicides that provide multiple
benefits to farmers and may have cash value of their own.
Rodriguez-Kabana explained that velvet bean is a tropical legume native
to Southeast Asia and related to soybean and kudzu. Velvet beans were
introduced into the southern United States in 1875, apparently by the
U.S. Department of Agriculture. Some southerners used the fast-growing
vines for shade around their homes. Farmers also used velvet beans for
a variety of purposes, especially after the discovery of a short-season
velvet bean that became known as the "Alabama" variety.
"Then, as now, nitrogen fertilizer was very expensive," explained
Rodriguez-Kabana. Because velvet beans are legumes, they can fix nitrogen
from the air and return it to the soil, so many farmers used it in lieu
of nitrogen fertilizers. Velvet beans also were used to control erosion,
build soil organic matter and as a forage and feedstuff for cattle,
said Rodriguez-Kabana. Southeastern farmers held the velvet bean in
high esteem until the 1950s, when two occurrences displaced the crop.
"After World War II, nitrogen fertilizer became much cheaper to
buy and soybeans became the glamour crop," said Rodriguez-Kabana.
During the 1960s, farmers began to plant soybeans because they promised
greater economic and nutritional value as a cash crop and feedstuff.
Velvet beans rapidly vanished from the southern landscape. "At
one time, there were about a million acres of velvet beans in the state.
Now there are only a few," said Rodriguez-Kabana.
About 10 years ago, Rodriguez-Kabana began exploring the use of velvet
beans and other plants as nematode-controlling rotation crops for cotton,
soybeans and peanuts. Nematodes are microscopic worms that infest soil
and cause major crop losses to row and vegetable crops. Nematodes severely
infest 10 to 15 percent of Alabama's major cropland and cause severe
yield reductions in cotton, peanuts, soybeans and many high-value vegetable
crops.
Rodriguez-Kabana explained that several types of nematodes infest southern
soils, including root-knot, cyst, reniform and lesion varieties. Synthetic
nematicides can be used to control these pests, but environmental concerns
are restricting access to and use of these chemicals. A natural control,
especially one that provides additional financial benefits for farmers,
would be a boon to southern agriculture.
The AU plant pathologist is exploring the effectiveness of various plants
that may be natural nematicides, including velvet and other beans, indigo,
sesame and various grass crops. Rodriguez-Kabana's management strategy
is to rotate acreage planted in traditional cash crops with one of these
rotation crops when it is profitable to do so. While several of these
crops control some nematodes, velvet beans effectively control a wide
range of these diverse pests.
"Velvet beans control most types of nematodes. There is no other
plant I know of that can deal with all these, and there are no nematicides
that can do that," stated Rodriguez-Kabana.
Velvet beans may also suppress weeds, diseases and insects and they
have potential as a cash crop, which means velvet beans can be viewed
as an organic, sustainable pesticide crop.
Rodriguez-Kabana noted that velvet beans can also help meet livestock
feed needs for the region. "The Southeast is deficient in cattle
feed and high quality feed has to be imported into the region from the
Midwest," he said. Velvet beans could be a source of forage and
feed, and they fit perfectly in the September-to-springtime niche when
Alabama forages are less available.
Bob Taylor, ALFA eminent scholar in AU's Department of Agricultural
Economics and Rural Sociology, has been pushing the pencil on velvet
beans to see how feasible they are as a rotational and cash crop for
the region. His calculations suggest that velvet beans have great potential,
and that potential has been enhanced by technological innovations.
Taylor explained that farmers who grew velvet beans in the past harvested
the seed pods by hand. Those velvety pods are covered with spiny hairs,
which makes hand harvesting a scratchy, uncomfortable and labor-intensive
job. Today, however, equipment exists that can harvest the entire plant,
including combining seed and baling vines for hay.
"Equipment dealers have told me that technology now exists to harvest
velvet beans for commercial use," said Taylor. "Velvet beans
could be used for hay, ensiled or even pelletized. What we don't know
is harvesting costs with current technology."
"Statistics in 1965 listed velvet bean selling at the farm gate
for 50 to 60 percent of the price of cottonseed meal," added Taylor.
"This price ratio suggests that velvet bean would be worth $100
to $120 per ton today as a high protein feed."
In addition, an active ingredient in velvet bean is L-dopa, a drug used
to treat Parkinson's disease. An AU pharmacologist will be analyzing
velvet bean as a possible source of this pharmacological agent, perhaps
opening additional markets for the bean.
While all this sounds promising, there are several obstacles to overcome
before velvet beans become a viable crop in the South. The first is
to convince farmers that rotating crops with velvet bean is worthwhile,
even before additional cash markets are developed.
"Rodriguez-Kabana's studies have shown that rotating crops with
velvet beans can increase yields of cash crops significantly,"
said Taylor. "We know that velvet beans can reclaim graveyard fields
(fields that are no longer in production because nematode populations
are so high) and also provide benefits for fields that are in production.
On some of the graveyard experimental plots, rotation of traditional
crops with velvet beans payed even if the velvet beans were not harvested."
"We are pushing the notion of on-farm participation in our research,"
Taylor continued. "If farmers can see the yield increases for themselves,
they may be more willing to adopt this management method."
Other obstacles to overcome are availability of seed and development
of registered velvet bean cultivars. David Weaver, professor of agronomy
and soils at Auburn and a prominent soybean breeder, is working with
Rodriguez-Kabana to establish a registered breeding line.
Weaver explained that controlled breeding programs for velvet beans
were not conducted in the first half of the 1900s when velvet beans
were popular. Though little seed is available, Weaver and Rodriguez-Kabana
have gathered as much seed as possible and have begun a breeding program
to select specific lines for seed propagation.
Tropical varieties of velvet bean typically mature about 200 days after
planting, which works well if velvet bean is used as a cover crop and
later grazed for winter forage. However, if the crop is to be harvested
for other purposes, velvet bean varieties that mature in 90 to 100 days
would be preferable.
"We want to evaluate the seed we have and find out how much variability
there is in the available germplasm," explained Weaver. "We
will be selecting for maturity dates, yield and other traits."
Much research must be done before velvet bean can become the true love
of southern agriculture, including answering questions about appropriate
livestock feeding regimes for the bean. However, these scientists and
others who are participating in AU's velvet bean research hope to soon
prove the crop's value so farmers will be willing to again embrace this
old flame.
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Katie Smith
4/24/97
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