Growing more with less water

John Diener is neck-deep in the drought. In three decades of farming, he said this is the worst year for water allocation. But his business has survived, and he credits the University of California with helping him make the most of his water.

Diener runs Red Rock Ranch in Five Points, southeast of Fresno, where he grows almonds, grapes, tomatoes and wheat. As a result of working with the UC system, he has turned to pivot irrigation, drip irrigation and other practices to optimize his water use.

"It's an ongoing relationship between agriculture and the university," said Diener, a UC Davis alumnus. "The university is the independent third party that helps the community and the legislators."

Water is the lifeblood of California's $37 billion agriculture industry. With the state in its third straight drought year, the race is on to use water more wisely. Over the years, UC has saved farmers millions of dollars with efforts to improve irrigation monitoring and management. Now UC researchers are rising to the current challenge by refining irrigation strategies, applying technologies such as aerial mapping and lasers, and developing drought-resistant crops.

The drought already is hurting the economy. Water restrictions in the Central Valley could mean up to $960 million in lost income and 16,150 to 23,000 fewer jobs, according to the latest provisional estimates by UC Davis agricultural economist Richard Howitt. But it would be worse if not for people such as Blaine Hanson, a UC Cooperative Extension irrigation specialist who has worked with Diener and other farmers.

"The drought definitely has (farmers') attention, and they're interested in some of these strategies to get by with limited water supplies," Hanson said.

Hanson is among the contributors to the UC Drought Management Web site, which launched in December. The site gives growers an easy way to view current research and appropriate drought strategies. It has irrigation information for almonds, pistachios, stone fruits, walnuts and alfalfa and soon will add wine grapes. UC also holds field days and short courses and offers helpful handbooks through the Agriculture and Natural Resources Catalog.

"We are providing information to farmers to help them irrigate more efficiently," said Terry Prichard, a UC Cooperative Extension water management specialist.

California growers annually save an estimated $65 million and reduce water use by about 100,000 acre-feet thanks to CIMIS, the California Irrigation Management Information System, a network of computerized weather stations developed in 1982 by the state Department of Water Resources and UC Davis. Diener is among its users, who can access data online for free about precipitation, temperature, wind speed and evapotranspiration, the combination of water transpired from the plant and evaporated from the soil and plant surfaces.

West side San Joaquin Valley farmers started using drip irrigation around 2000 after UC showed they could use it on salty soils and make more money than with sprinklers or furrow irrigation, Hanson said.

Now, most Fresno farmers use drip irrigation to water tomatoes and other vegetables, generating higher yields and other benefits such as reduced salinity. Statewide, drip also is popular for irrigating orchards, strawberries and wine grapes.

Stressful irrigation

Two other steps that can improve irrigation efficiency are better scheduling (for example, not over-irrigating) and deficit irrigation (stressing crops at certain times to reduce water use with minimal impact on yield and quality).

UC's deficit irrigation research has helped Northern California wine grape growers reduce water use by 30 percent and increase the quality of their crop, Prichard said.

Deficit irrigation also works with almonds, pistachios and some orange varieties, said David Goldhamer, a UC Cooperative Extension irrigation specialist.

The key to deficit irrigation is monitoring plants for stress, but until now it's been impossible to get accurate measurements that characterize entire fields. Goldhamer says aerial imagery will now allow water stress estimates for each plant or tree in a field. He worked with a Spanish team that took images from robotic aircraft flying at 1,000 feet. Given regulatory and costs concerns, he thinks a more viable option could be using high-resolution cameras on conventional aircraft flying at 15,000 to 20,000 feet.

"I think it's doable," Goldhamer said. "In 30 years, this is the technology that I am by far the most excited about."

Goldhamer has enjoyed working at UC on water management issues, calling the growers with whom he has collaborated "unsung heroes" for having research conducted on their fields.

Lasering in on water use

A new generation of UC researchers has a well of ideas. Jan Kleissl, a UC San Diego assistant professor of environmental engineering, is looking to help with lasers.

The large aperture scintillometers — instruments originally intended for military target tracking — use lasers to help measure evapotranspiration. Kleissl has tested the technology in the Imperial Valley and New Mexico, and is seeking a grant so he can analyze the data.

The technology isn't cheap: Each scintillometer costs $25,000 and it's best to use two. Kleissl said it's a way to calculate evapotranspiration over a long distance — the instruments cover up to 3 miles — that could cut agricultural water use by at least 10 percent.

Developing drought-resistant crops

UC researchers aren't only trying to improve irrigation efficiency, they're also trying to engineer drought-resistant crops for use in California and around the world.

A study published this spring by UC Riverside assistant professor of cell biology Sean Cutler suggests that stable synthetic chemicals could be sprayed on plants to enhance drought tolerance and improve yield.

UC Davis professor of cell biology Eduardo Blumwald has been working for seven years to develop genetically engineered plants that can survive droughts and grow with significantly less water. Collaborating with Arcadia Biosciences of Davis, he began testing with tobacco plants and now is experimenting with rice, wheat and tomatoes.

"We are advancing steadily," Blumwald said. "We are finding we can get relatively high yields with low water, which is ideal."

Greenhouse trials are taking place now, with commercialization a few years away, he said.

Blumwald, who came to UC Davis in 2000 from the University of Toronto, said he feels a clear mandate to address the state's needs.

"We have taken the drought as a very personal challenge in California," Blumwald said. "There is no choice. We are really racing time."

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