Forages for Irrigated Areas
By Amy Spillman
May 22, 2002
Alfalfa may help solve a problem
thats been plaguing farmers and land managers for years in California,
according to scientists with the Agricultural Research Service and their
The states San Joaquin Valley is one of the worlds most
productive agricultural areas, sometimes referred to as the nations
salad bowl. Unfortunately, the irrigation systems that bring water to the
valleys fruits and vegetables also transport salts that thwart plant
growth. Salt makes it harder for plants to absorb the water they need.
In view of the restrictions on discharge of drainage waters and in an effort
to use water more efficiently, members of the federal/state interagency
Joaquin Valley Drainage Implementation Program recommended that farmers
plant salt-tolerant vegetation and use saline drainage water to irrigate it.
A few years ago, ARS scientists at the
George E. Brown, Jr., Salinity
Laboratory in Riverside, Calif., tested eucalyptus to see if it would be
effective at extracting excess saline drainage water. They found that although
eucalyptus trees can survive on a diet of salty water, they suffer from salt
stress. The trees dont die, but they dont grow either, so they
dont use up very much of the saline water.
Since then, the scientists have turned their attention from eucalyptus to
salt-tolerant forages--plants that could possibly reduce drainage water volumes
while producing a feed source for sheep and dairy cattle. Along with
collaborators at the University of
California-Davis and California State
University-Fresno, the salinity lab scientists conducted a controlled study
to evaluate promising forage crops.
The researchers used an elaborate sand-tank system at the salinity lab and
tested a variety of forage species. They ranked these species by factors such
as production potential and forage quality. Overall, alfalfa cultivars
performed best under the controlled conditions of the experiment. Although the
results are promising, the researchers will conduct field tests and ruminant
nutritional studies before they make any recommendations.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.