Quenching Plants' Thirst-Below Ground
The Tomato Magazine
Imagine having a refreshing drink of water brought to
you every time you wanted. That happens to thirsty plants irrigated with
what's known as a subsurface drip irrigation system. This environmentally
friendly technology employs an underground network of sturdy, flexible
black tubing to carry water to plant roots, exactly where they need it
About a decade ago, scientists with the Agricultural Research Service's
Water Management Research Unit--then located in Fresno, Calif., but now
based in nearby Parlier--extensively tested subsurface drip irrigation
of tomatoes, cotton and corn. Today, their investigations still remain
among the most comprehensive of their kind, documenting that the below-ground
systems can provide higher yields while, at the same time, using less
water than other systems.
These early findings are important: As competition for high-quality water
continues to heat up between farms and cities, some growers are now taking
a new look at subsurface drip. Conducted in California's Central Valley,
the research is also applicable to farms in many other states.
Subsurface-drip irrigation enables growers to send precise amounts of
water to roots. The underground tubing also can transport fertilizers
with vital nutrients--like phosphorus and nitrogen.
A buried-drip system can conserve water by allowing growers to apply it
more precisely than if they were to choose some other kinds of irrigation
equipment, such as overhead sprinklers. This precision helps growers avoid
over-irrigating their crops. In turn, they reduce the risk that unused
nutrients would be carried by irrigation water into the underground water
supply--where they might become pollutants.
What's more, because the water is applied underground, protected from
direct exposure to sun and wind, less of it is lost to evaporation.
That's not all. Irrigation water that's applied underground doesn't sit
on the soil surface, of course. Keeping the soil surface dry makes it
less hospitable for plant-damaging microbes that thrive in moist soil.
ARS is the U.S. Department of Agriculture's chief scientific research
© 2005 Columbia Publishing
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