The Palo Verde Irrigation District in Southern
California is trying deficit irrigation on alfalfa,
the most widely grown crop in the Colorado
River Basin.
Alfalfa, which is harvested as hay to feed
horses and cattle, can be cut and baled
several times a year in some climates. The
Palo Verde district is experimenting with
reduced water for the midsummer crop,
which requires more irrigation but produces
lower yields.
Sensors placed over the test plots indirectly
measure how much water the plants are
using, and the harvested crop is weighed to
determine the yield.
“The question then becomes, what’s the
economic value of the lost crop versus the
economic value of the saved water?” said
Bart Fisher, a third-generation farmer and a
member of the irrigation district board.
Blaine Carian, who grows grapes, lemons and
dates in Coachella, California, already uses
deficit irrigation. He said withholding water at
key times improves the flavor of his grapes by
speeding up the production of sugar.
He also uses on-farm weather stations and
soil moisture monitors, keeping track of the
data on his cellphone. His drip and micro-spray
irrigation systems deliver water directly to
the base of a plant or its roots instead of
saturating an entire field.
For Carian and many other farmers, the appeal
of technology is as much about economics as
saving water.