Finding Hope Amid Enduring Drought
Researchers at UC Davis College of Agricultural and Environmental Sciences are working with growers, industry, and agencies throughout the state to find practical solutions. Here’s a quick look at some of the latest developments.
Professor Helen Dahlke with Land, Air and Water Resources and her team are making headway with groundwater banking, where excess surface water during storms and flood releases is directed to select fields to serve as infiltration basins to replenish aquifers. Dahlke’s team just began a two-month test in an alfalfa field near Scott River in Siskiyou County, applying water in various amounts to analyze soil saturation, infiltration rates, and whether the winter irrigation adversely affects the alfalfa.
The team hopes to launch similar projects in Orland in Colusa County, where many growers rely solely on groundwater, and in the lower Tulare River area of Tulare County. Groundwater projects with the California Almond Board are also in the works.
River water for Central Valley farmers was reduced by one-third last year, and 425,000 acres of the world’s most fertile land lay fallow. Are there practical ways growers can stretch water without reducing crop production, quality and yield?
Yes, according to results of a water-saving project in Pajaro Valley in Monterey County led by Professor Samuel Sandoval Solis, Cooperative Extension specialist with Land, Air and Water Resources. Groundwater overdrafts were so high in Pajaro Valley last summer that the region’s aquifer sank below sea level, causing saltwater intrusion. Sandoval’s team identified steps that conserved 5,100 acre feet per year – 41 percent what was needed to avoid overdraft – without sacrificing crop quality and yield.
Sandoval’s recommendations focused on optimizing irrigation, finding that line between applying too much and too little water. There are many variables, and our experts are helping remove the guesswork.
Example: UC Davis plant physiology professor Ken Shackel is part of a five-year experiment in Merced, Kern and Tehama counties to see how different irrigation levels affect almond yields. Shackel’s team is applying 70 to 115 percent of recommended irrigation levels based on weather-station data, and monitoring orchards weekly. Two years in, preliminary data indicates yield may start to drop at about 90 percent. Stay tuned.
More growers are using pressure chambers, devices developed at UC Davis that measure a plant’s water needs directly by gauging how hard a plant is working to pull moisture from the soil. Shackel and his colleagues recently developed an interactive, online tool to help growers interpret pressure-chamber readings. Meanwhile, Professor David Block with Viticulture and Enology and his team are designing a grapevine irrigation system that applies water based on each vine’s individual needs.
Breeding drought-tolerant crops
Our breeders are developing new varieties of food and fiber that can thrive in dry, saline conditions. Plant sciences Professor Eduardo Blumwald is working to develop rice varieties that don’t shut down in drought conditions, but rather continue to produce the nutrients necessary to make rice grains.
Plant sciences Professors Jorge Dubcovsky and Jan Dvorak are mapping, isolating, and cloning genes from the massive wheat genome, investigating critical stages of development. Dubcovsky’s lab recently identified a region of a rye chromosome that, when introduced into wheat, increases yield and improves the water status of the plant under limited irrigation. Dvorak’s lab is working to develop a novel salt-tolerant forage crop that could be irrigated with poor-quality drainage water.
Viticulture and enology Professor Andy Walker is breeding drought- and salt-tolerant grape rootstocks by optimizing root architecture to improve water-use efficiency.
Producing wine, food and landscapes with less water
A typical winery uses four to six gallons of water (after the grapes are harvested) to produce one gallon of wine, most of that used to wash equipment. At our new Jess S. Jackson Sustainable Winery Building, researchers are developing self-cleaning fermentors capable of recycling 90 percent of that water. The goal: affordable technology that uses one gallon of water to produce one gallon of wine.
Our food science faculty, like Professor Chris Simmons, are working with food processers, inspecting and analyzing every pipe and plant procedure to find inexpensive ways to save water and energy.
We’re also helping Californians save water in their own backyard. At the UC Davis California Center for Urban Horticulture, experts like David Fujino are providing information on irrigation management and drought-tolerant plants to reduce urban water use and prevent runoff from landscapes.
There’s no one, simple way to deal with California’s drought. But together, I know we can find long-term solutions for managing our vital, scare water resources.
Helene R. Dillard is dean of the UC Davis College of Agricultural and Environmental Sciences. Prior to her appointment in 2014, Dr. Dillard was on the faculty at Cornell University as a plant pathology professor and extension expert in the biology, ecology, and management of fungal pathogens that cause diseases in vegetable crops. She was born, raised, and educated in California. This article was originally published by AgAlert on March 4, 2015.