Laserfiche WebLink
<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. <br />