<br />soak gradually into the soil, as evidence of ineffi-
<br />cient use. Critics also contend that farmers could
<br />use less water if they changed cropping patterns
<br />to grow higher-value, less water-intensive crops,
<br />retired marginal lands, and adopted "sustainable"
<br />farming methods.
<br />
<br />
<br />Agricultural Conservation
<br />
<br />Three-fourths of California's developed surface water
<br />is used by agriculture. Because farming is a water-
<br />intensive industry, farmers have felt their supplies
<br />squeezed in recent years by declining water alloca-
<br />tions brought on by drought, growing competition
<br />from urban users, concerns about groundwater
<br />overpumping, and increasing water demands for fish
<br />and wildlife.
<br />
<br />Rainfall in California rarely occurs during the peak
<br />growing season in the areas of heaviest cultivation,
<br />so farmers rely almost entirely on artificial "rainfall,"
<br />or irrigation water. Thus, a farmer's ability to manage
<br />water use without reducing crop yield becomes not
<br />only a hedge against water-supply fluctuations but
<br />also a way to cut overall production costs and ensure
<br />long-term economic viability.
<br />
<br />As the single largest water-consuming industry,
<br />agriculfure has become a focal point for efforts to
<br />promote water conservation. This became especially
<br />true in the late 1980s and early 1990s as the drought
<br />reduced surface water supplies and federal laws
<br />required more instream flows for
<br />the environment. In those few
<br />years, water conservation took
<br />on added importance for farmers.
<br />Indeed, the number of state, federal
<br />and local programs devoted to
<br />increasing the efficiency of water
<br />use in agriculfure has multiplied.
<br />
<br />
<br />Ra;,~f(tll in California rarely
<br />OCC/lrs during fhe peak
<br />growing scason ill the arcas
<br />(~f heal'ieSI elilfil,atioJl, so
<br />fanners rely almosf entirely
<br />Oil artificial "rah~fall, ..
<br />or irrigatioJl ~\'{lter.
<br />
<br />8
<br />
<br />One collaborative federal-state-
<br />local program is a fleet of mobile
<br />laboratories that have provided
<br />more than 2,500 on-site irrigation
<br />evaluations to California farmers
<br />since 1982. Originally supported by
<br />funding from the sfate and about 60
<br />water agencies and resource
<br />conservation districts, as well as
<br />in-kind services from the U.S.
<br />Department of Agriculture, the mobile labs assess
<br />individual farmers' irrigation systems and practices
<br />and recommend ways to improve efficiency. "As a
<br />result of the mobile lab field test, I was able to see
<br />that with a little inexpensive maintenance, we could
<br />make better use of our water, get it where we need
<br />It, and improve the field efficiency of our pumping
<br />engine," said one grower after seeing the mobile lab
<br />in action.
<br />
<br />Discussions about agricultural water use often
<br />become polarized. Environmentalists cite practices
<br />such as flood or furrow irrigation, in which entire fields
<br />or furrows are covered with water that is allowed to
<br />
<br />One 1995 study released by the Pacific Institute
<br />suggested that irrigation water used in California
<br />agriculfure could be reduced by 3.5 million acre-feet
<br />by 2020 if farmers shifted from growing water-inten-
<br />sive, low-value crops such as alfalfa, cotton and rice,
<br />to growing crops that have higher market value, such
<br />as almonds, grapes, artichokes and olives, and used
<br />water efficient irrigation technologies. The Pacific
<br />Institute said its recommendations could raise farm
<br />income, cut surface water and groundwater use, and
<br />reduce agricultural drainage problems.
<br />
<br />But farmers counter that the real issue is not the
<br />type of irrigation used or crop choices, it is the
<br />efficient management of irrigation systems. If
<br />managed properly, they say, the flood and furrow
<br />irrigation techniques in use in many areas are
<br />efficient. As far as crops, farmers say crop choice is
<br />- and should continue to be - determined by the
<br />market forces of supply and demand, and not be
<br />mandated by water use.
<br />
<br />Most of the state's soil drains well, so irrigation water
<br />that is not used by crops washes harmful salts from
<br />the soil and replenishes groundwater. Tailwater
<br />runoff. the water that drains from an irrigated field,
<br />typically is reused by farmers on another field or
<br />sometimes 10 preserve wetlands. However. some
<br />areas, primarily on the west side of the San Joaquin
<br />Valley, have poor drainage, and excess irrigation
<br />water contributes salts to shallow groundwater.
<br />
<br />There has been a protracted debate over whether
<br />this land should continue to be farmed. Critics say
<br />much of the poor-draining crop land should be
<br />retired from production, but farmers are employing
<br />sophisticated irrigation management techniques that
<br />reduce the amount of water used, reducing the
<br />volume of salty drainage outflow or contributions
<br />to the shallow groundwater table. New irrigation
<br />technologies such as subsurface drip systems and
<br />more precise sprinkler controls for pre-irrigation
<br />also have helped growers in areas with poor drain-
<br />age to improve their water management practices.
<br />In areas with porous soils, where water moves too
<br />quickly through the soil, growers are experimenting
<br />with synthetic polymers that help hold moisture in
<br />the soil, making it available longer for absorption
<br />by plants.
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