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system used on romaine lettuce in Coachella Valley, California. Click the
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Research Aims to Improve Fertigation for
Farmers By Jan
Suszkiw November 10, 2004
Getting the most from fertigation--nourishing crops with water and
chemical fertilizers simultaneously--using different irrigation systems is the
goal of Agricultural Research Service
scientists seeking to devise best management practices for farmers.
Fertigation's advantages include a capacity to nourish crops
throughout the season using less nitrogen and other fertilizers. Despite
reducing time and costs associated with irrigating and fertilizing crops
separately, fertigation still has room for improvement. One area ARS scientists
are working on is delivery--putting nutrients where they're needed and at
At the ARS
Water Conservation Laboratory in Phoenix, Ariz., soil scientist
Adamsen and agricultural engineer
Hunsaker are identifying the optimal timing of mixing fertilizer with
irrigation waters. In a study with date palms on sandy soils in California's
Coachella Valley, the scientists observed that the fertilizer applications were
most uniform when the fertilizer was added during the entire irrigation
process, rather than for part of it.
In Lincoln, Neb., at the
Soil and Water Conservation Research Unit, research leader
Schepers and colleagues are testing the use of high-clearance canopy
sprayers equipped with electronic sensors. For example, prior to fertigation,
the sensors zap the crop with certain light wavelengths to check for the onset
of stress due to nitrogen deficiency. The sensors then assign a numeric value
to the returning light. The canopy sprayers use this information to fertigate
with variable rates of nitrogen based on the plants' needs, saving money and
reducing the risk of leaching surplus nutrients.
Bryla, a plant physiologist formerly with the ARS
Management Research Laboratory in Parlier, Calif., tested the use of
subsurface drip-irrigation systems to fertigate newly planted peach trees.
Through subsurface tubes, the system delivered precise amounts of water and
fertilizer directly to the trees' roots in a highly efficient manner, according
to Bryla, now at the ARS
Crops Research Unit in Corvallis, Ore.
about fertigation research in this month's issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.