January 3, 2009

Technology Could Help Farmers Conserve Water

Farming may soon be revolutionized through an unlikely method, the laser.

Jan Kleissl of the University of California believes laser technology can be used as a way to conserve millions of gallons of water when farmers water their crops.

Kleissl and his team of students are using a scintillometer to measure the amount of water crops lose to evaporation, and are finding the peak times in which water disappears.

The researchers hope to help farmers see how efficiently their water is being used.

"What's new about our approach is the monitoring side of it," Kleissl said. "We're trying to improve on that."

Until now, farmers often managed their irrigation systems by sight, but recent droughts have made sophisticated water conservation methods a necessity.

In California last year, a federal judge ordered that pumping in the Sacramento-San Joaquin River Delta be restricted to protect the delta smelt, a native fish.  The action made water an even greater commodity, and cut into growers' water supply.

New restrictions could now be imposed to protect another fish, the longfin smelt.

According to Khaled Bali, an irrigation expert for the University of California Cooperative Extension, these shortages are forcing scientists to find new ways of determining how to irrigate and use water.

"There's not enough water to go around," Khaled added.

One farmer in the region, Bob Polito, was forced to remove one sixth of his farmland from production due to the pumping restrictions. 

Polito welcomes the new methods, but says new technology to help with irrigation has proven to be too expensive thus far.

"Anything that gives you an accurate accounting on that score would be a help to farmers," Polito added.

Researchers are also testing other methods to conserve water.

One method is to use a device to measure the speed that sap creeps up a tree.  If the sap movement on a tree slows, it means the trees need less water.

Another method uses satellite imagery to measure "evapotranspiration," which is the amount of water lost to the atmosphere from plant and soil surfaces.  The method is a new spin on the historic evapotranspiration formulas most farmers already use to create their irrigation strategies.

Kleissl and his team hope to provide farmers with better information by using the scintillometer, a device that uses lasers to measure heat flux evapotranspiration over long paths.

The researchers are using the device to record the fluctuations in the air that is caused by temperature and humidity changes.

The scintillometer sees waves similar to the way we see heat radiate from asphalt, only in greater detail.

Kleissl and his students hope the tool will allow farmers to more accurately measure how much water is lost to evapotranspiration.

The study, which is expected to last two years, is currently underway on a University of California farm.

The scintillometer is being used to measure one half of the property, while normal irrigation methods are being used on the remaining half.

If the results show considerable water savings, the team hopes to see scintillometers on farms across California.  Kleissl believes that 10 could be used to cover a wide range of property across the state, and would cost around $700,000 to install.

According the David Zoldoske, of the International Center for Water Technology at California State University, the scintillometer method is showing signs of hope, but will probably not be the end-all of water conservation analysis.

Zoldoske believes the tool will be best suited to work in conjunction with tools that analyze a plant's water needs.

"It's simply just another way to have good information," he said. "It's like your doctor: If he can measure your pulse and some other things, that really helps him manage your health. It's the same with plants."


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