Overton, Texas
August 27, 2007
Rio Verde
lablab, a recently released forage legume by the
Texas Agricultural Experiment
Station, could provide some relief to nitrogen fertilizer
cost-shock.
Not only does it not require nitrogen fertilizer, Rio Verde
lablab is found palatable by both cattle and wildlife, said its
developer, Dr. Ray Smith, Experiment Station plant breeder based
at Overton.
Natural gas is used to produce nitrogen fertilizer, and its rise
in cost raised fertilizer prices. High nitrogen prices hammer
row crop producers and livestock producers too. Today's highly
productive, improved pasture grasses require large amounts of
nitrogen, Smith said. However, Rio Verde, as do other legumes,
fixes nitrogen from the atmosphere.
About 80 percent of the Earth's atmosphere is nitrogen gas, but
it's not in a form plants can use. Forage legumes have symbiotic
relationship with rhizobium bacteria that live in small nodules
on the plant's roots.
They take nitrogen gas in the air and convert into a form of
nitrogen that plants can use.
Smith envisions several production niches for Rio Verde, he
said. It could be incorporated a component of wildlife food
plots, as livestock grazing, or as a hay crop or as a green
manure crop. A green manure crop is one not harvested but tilled
into the soil to improve fertility.
"And we developed this new cultivar with Texas seed production
in mind," he said.
Prior to Rio Verde's release, seed for all other lablab
varieties was grown in Australia, Smith said. This was because
other varieties were too late in maturing to produce a seed crop
in Texas before being killed by the first frost.
"The forage production and nutritive value potential of Rio
Verde is about the same as iron and clay cowpeas û about 25
percent," Smith said.
"Compared to bermudagrass, it's generally going be higher in
protein."
But while cattle don't like cowpeas, they find lablab forage
highly palatable, he said. White-tailed deer, which can be picky
eaters, will also readily browse lablab, making it a good,
low-management crop for supplemental feed in wildlife plots.
Usually, the development of a new forage cultivar by
conventional plant breeding techniques requires at least eight
to 10 years, Smith said. Though first selections of parent
plants were made in the mid 1990s, its development was not
considered a high-priority project. Nitrogen prices were low and
producers were not interested in summer forage legumes.
As nitrogen prices rose, in 2003, Smith and his Experiment
Station colleague, Dr. Monte Rouquette, felt it necessary to
speed the process up to meet the emerging market for new forage
legumes.
To accelerate the project, they enlisted the help of Experiment
Station scientists at Dallas, Stephenville and Beeville. Also,
the Texas Foundation Seed Service and three Texas seed companies
cooperated to speed
up commercial seed production.
It's too late to plant Rio Verde for a summer forage or hay crop
this year, but there's still time to try it out in wildlife
supplemental food plot, Smith said.
He recommended planting about 25 pounds of seed per acre.
Rio Verde tolerates acidic soils reasonably well, Smith said.
"We've grown here in soils down to about pH 5.5 with good
results," he said. "It's not something that will take extreme
acidity, but it is better at moderate levels of acidity than
some of our other crops."
For summer forage and hay programs, Smith recommended planting
from 30 to 50 pounds per acre.
"Use a drill to place seed about 1 to 1.5 inches deep," he said.
"An alternative planting method is to broadcast seed on disked
seed bed and follow with a light disking to cover. Use care to
not cover the seed more than about 1.5 inches deep."
With adequate soil moisture, the legume can be planted from May
through July, Smith said. It will start flowering in late August
but will remain productive until the first hard frost.
Rio Verde is adapted to sandy, sandy loam, clay loam and clay
upland soils, including the Texas regions of the Pineywoods,
Gulf Prairies and Marshes, Post Oak Savannah, Blackland
Prairies, Cross Timbers and Prairies, and South Texas Plains,
Smith said.
Current prices for Rio Verde seed are about $4.50 a pound. The
seed is available from
Turner Seed in Breckenridge. The seed company's phone number
is 800-722-8616. |
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