Jim Morris had lots of reasons for embracing a University of California research project to use his alfalfa field for groundwater recharge.
His operation, the Bryan-Morris Ranch in Etna, Calif., has emphasized environmental stewardship since his wife’s family started it in the 1850s. The ranch was the site of soil conservation and other studies as long ago as the 1940s.
Morris also believes that being seen as using sustainable practices will help growers become less of a target for critics, he says.
So Morris gladly allowed his ranch to be one of two sites that UC-Davis and UC Cooperative Extension scientists used to flood established alfalfa stands with storm water during the winters of 2015 and 2016.
The study’s initial results were published earlier this year in the UC’s journal California Agriculture, asserting that alfalfa can tolerate very heavy winter flooding for groundwater recharge.
“I think there’s a tremendous future” when it comes to recharge projects in alfalfa fields, Morris says. “For people who are looking for ways to benefit the aquifer under SGMA (the Sustainable Groundwater Management Act), it could be one of the more important tools they have.”
But Morris still has plenty of questions he’d like to see answered in the next round of research, including how long it takes the water he floods his field with to get back into the Scott River. Answering this question might reassure critics who think he just wants to bank the water for his own use, he says.
Other questions may arise as the work continues, he says.
“I think there will be a lot of things we want to know, but we just don’t know what they are yet,” he says.
Morris has more than 300 acres in alfalfa and grass hay production and raises Suffolk/Hampshire-cross sheep and Angus cattle. Jim and wife Katie married in 1988 and are partners with Katie’s father, Mike Bryan, in running the ranch.
Their ranch in the scenic Scott Valley about 30 miles south of the Oregon-California state line and another farm near Davis were selected for the research because the soils in those areas have relatively high water percolation rates, university officials say.
“We found that most of the applied water percolated to the groundwater table,” wrote lead author Helen Dahlke, an integrated hydrologic science professor at UC-Davis.
The alfalfa endured saturdated conditions in the root zone for a short time, but the yield loss was minimal, noted Dahlke and her coauthors – USDA Natural Resources Conservation Service soil scientist Andrew Brown, UCCE specialists Dan Putnam and Toby O’Geen and the late UCCE advisor Steve Orloff.
The scientists noted that the alfalfa trial’s results show tremendous potential for the state’s groundwater basins. They estimated that if all the suitable alfalfa acreage were flooded with six feet of winter water, and assuming 90 percent percolates past the root zone, it would be possible to bank 1.6 million acre-feet of groundwater each year. The calculation was based on an index created by O’Geen that identifies areas where soils are suitable for on-farm groundwater recharge.
By comparison, Lake Oroville, the second-largest reservoir in the state, has a storage capacity of 3.5 million acre-feet, Dahlke wrote. An acre-foot is about 326,000 gallons, or enough water to serve an average California household for a year, according to the Water Education Foundation.
The alfalfa research was the latest in a series of projects by UC researchers studying the effects of using farmland to capture and bank winter storm water. Other scientists are looking at recharge efforts in almond orchards and vineyards. Such projects have great promise but also often require collaboration among numerous jurisdictions and agencies, the UC explains in a news release.
The alfalfa trials were paused after the death of the Siskiyou County-based Orloff last fall, Morris says. Orloff was instrumental in leading many water conservation-related projects along the Scott River, a key Klamath River tributary and a spawning ground for endangered salmon. Low levels in the Scott have prompted legal challenges and led to state restrictions on irrigation.
An overall lack of water and other complications prevented researchers from doing field trials last winter, but scientists do plan on doing more research this winter, Dahlke told Western Farm Press in an email.
Researchers plan to use two commercial alfalfa fields as well as a field at the Kearney Agricultural Research and Education Center to test the effect of modest and high amounts of winter water application on growing-season alfalfa yield in different soils and under different climate conditions, Dahlke says.
“In addition, we will quantify how winter water application affects growing season water balance and irrigation demand,” she says.
Much of the research in the next round will focus on the Central Valley’s southern end, where alfalfa is grown but doesn’t go dormant because of the warmer climate. Applications on Morris’ farm have been done when the alfalfa is dormant.
In the Scott Valley, the only time sufficient water is available for recharge is during big winter rains and snow melt in the early spring, Morris says. He tried applying different amounts of water in different segments of the field to learn how much water his alfalfa could take without losing yields, and found that fields with suitable, well-draining soils could work for recharge.
But if the plants are actually growing, too much water saturating the roots for too long will kill the plant, he says. And most growers don’t want to fallow fields because it isn’t economically feasible, he says.
Among other things for growers to consider is that the times he was flooding his fields for recharge are typically when growers want to put on herbicides. He wouldn’t want to use most herbicides when putting water in the aquifer, and eventually the river, so it creates a weed problem, he says.
Morris has responded by over-seeding with orchard grass, which edges out weeds and creates an alfalfa-orchard grass mix, he says.
Another issue is that obtaining state permits for taking offseason storm water from the irrigation ditch for recharge can be a lengthy process, and growers may not see it through considering there’s no economic benefit from doing a recharge project.
“I think that will be streamlined over time,” he says.