From the Klamath Basin to the Rio Grande, water continues to be California’s most disputed resource, as urban, environmental and agricultural users spar over this valuable but limited commodity. Peer-reviewed research articles and an editorial in the July-August 2002 issue of California Agriculture focus on some of the ways UC scientists are helping California growers to irrigate crops more efficiently, while the in-depth cover news story explores how UC continues to respond to last year’s water crisis in the Klamath Basin.

“The intensity of competition for water means that some reductions in agricultural water supplies are probably inevitable,� Henry Vaux Jr., assistant vice president of the UC Division of Agriculture and Natural Resources, writes in an exclusive California Agriculture editorial. “Extensive research efforts must be mounted to develop the scientific knowledge needed for new and innovative technical and managerial irrigation regimes that will allow agriculture to adapt to diminished water availability.�

For example, during last year’s severe drought, hundreds of Klamath Basin farmers did not receive irrigation water, so that flows and lake levels could be maintained for three endangered fish species. Staff and scientists at the UC Intermountain Research and Extension Center (IREC) near Tulelake, Calif., served as important advisors to growers, government agencies and the public. IREC Superintendent Harry Carlson told California Agriculture, “The crisis was a wakeup call that this is serious and decisions have wide-ranging impacts. The stakeholders are determined to develop more of a planned response so future water shortages don’t come as such a drastic shock.�

In addition to the Klamath Basin news article, California Agriculture’s special focus on irrigation efficiency includes the following:

• Pumping plant efficiency:
  
  While a statewide program is encouraging growers to upgrade their irrigation pumping plants, energy savings may not necessarily result. Contact: Blaine Hanson.
  
  
• Garlic irrigation:
  
  A 4-year study found that garlic irrigation should be managed based on soil type; crops grown in sandy soil require more regular irrigation whereas crops in clay soil may not need as much water. Contact: Blaine Hanson.
  
  
• Salt tolerance of landscape species:
  
  Increasingly, landscape plants are being irrigated with reclaimed water, which tends to have high salt concentrations. In a news progress report, UC Davis environmental horticulturalists provide a table detailing the salt tolerance of 50 common landscape species. Contact: Lin Wu.
  
  
• Buried drip irrigation for pistachio:
  
  High humidity in pistachio orchards increases the risk of the fungal disease Alternaria late blight, which is resistant to fungicides. UC scientists, using environmentally safe buried drip irrigation, found that this method significantly reduced orchard humidity, resulting in fewer leaf symptoms, a higher rate of shell splitting and more marketable pistachios compared with flood irrigation. Contact: David Goldhamer.