Samer Naif, a student at the University of California, San Diego, sits on an Alfalfa illometer transmitter in bright, California.This is a laser device that can measure evaporation and help to accurately calculate how much water is needed for proper irrigation.(AP Photo/Ric Francis) lessSamer Naif, a student at the University of California, San Diego, sits on a scinillometer transmitter at an Alfalfa field in Blythe, California.This is a laser device that can measure evaporation and help to accurately calculate how much water is needed for proper irrigation.(AP Photo/Rick Francis) under 70Six years after the invention of the modern sprinkler helped the agricultural revolution, an environmental engineering professor pointed a laser beam to a alfalfa crop in southern California --Dry Imperial Valley, look for a better way to preserve the millions of gallons of water sprayed on thirsty crops every year.In January, Kleissl and several of his students at the University of California, San Diego, installed a telescope.A device, known as a large aperture flicker meter, is used to study how much the crop loses by evaporation and the peak time when the water disappears.Hope to give farmers a more accurate, more upwardto-Their crops use water more efficiently than the current technology allows."What's new about our approach is its monitoring," Kleissl said over the phone in his office ."."We are trying to improve this."Some of the advances in irrigation are focused on the water supply system --For example, the 1932 horizontal-action impact-driven sprinkler invention of Orton Englehart, a Southern California grower, obtained a patent for the invention in the second year.But while most farmers are experts in Visual Management of irrigation, drought in recent years requires the use of more sophisticated methods --and save -water.Last year, when a federal judge ordered federal and state agencies to limit pumping in Sacramento, water became a more valuable commodity in California.The San Joaquin River Delta protected threatened Delta smelters, severely cutting the supply of growers.Last month, state fish and wildlife managers decided to limit pumping to protect another native fish, the long-fin tuna, which could lead to further restrictions.Khaled Bali, an irrigation expert at the University of California's Imperial County co-promotion office, said these shortages prompted researchers to design new methods to determine when to irrigate and how much water to use."There is not enough water around," he said .".Kleissl's team wants to provide farmers with more valuable information by using a flicker meter, which focuses the laser beam on the farm site, and record the fluctuation of air refractive index caused by factors such as temperature and humidity changes.The device sees similar waves in the air that people see from the highway sidewalk on a hot day.But the flicker can see these waves in more detail.It is hoped that farmers will eventually be able to use lasers to measure the amount of irrigation water in farmland more accurately.Kleissl's preliminary test of the technology was designed to measure the evaporation of the alfalfa crop to determine the months in which the yield was low and the rate of evaporation was high.These data will allow farmers to rest their crops at the lowest efficiency and use water for other applications.Especially in the Dry Valley of Kings in California's southernmost desert, one possible scenario is that in the hot summer months, when the output is smaller and more water is needed, let the alfalfa crop take advantage of production in the other three seasons.His research will take at least two years to complete and is currently being conducted at an experimental farm run by the University of California promotion program.About half a field.Miles a quarter.A particularly thirsty crop, alfalfa grass, was planted a mile wide.It is also the most common crop in the Imperial Valley, about 200 miles southeast of Los Angeles, where rainfall averages less than 3 inch a year, and high temperatures typically exceed 100 degrees in the months of the year.Half of the fields measured were blinkers, and the other half were traditional farming and irrigation.If the test shows that a lot of water is saved, Kleissl would like to see the flashing meter placed in the agricultural area around the state.He estimates that 10 farms can cover a wide range of farms across California, and the initial investment could be between $500,000 and $700,000, although this does not include the cost of maintaining and monitoring them.David zordorsk, head of the International Water Technology Center at California State University Fresno, said the flashing meter project showed hope, but it is best to use it in conjunction with other technologies that produce and analyze data on plant water requirements."This is just another way to get good information," he said ."."It's like your doctor: It really helps him manage your health if he can measure your pulse and something else.The same is true of plants.