Avocado growers get advice on saving, managing water
San Diego County used to be home to nearly 25,000 acres of avocado trees, but to- day, there are about 14,000. The decrease is largely due to rising costs associated with av- ocado production, namely the cost of water. John Burr, who has been growing avoca- dos for 15 years, said irrigation represents more than half his annual production costs, and meeting the needs of his trees is a constant challenge. Burr said he is hopeful that ongoing re- search may help avocado growers deter- mine the evapotranspiration more accu- rately in an avocado grove. He said water use information specific to avocados is critical to how growers select tools to de- termine irrigation run times. With these concerns in mind, avocado growers gathered at the San Diego County Farm Bureau office in September for an avocado irrigation workshop facilitated by Ali Montazar, University of California Cooperative Extension irrigation and water management advisor for Imperial, Riverside and San Diego counties. “All of our information being developed right now is focused on (irrigation) effi- ciency,” Montazar said. “Growers want to know how much water they need and what tools they should use to be more efficient.” Burr said growers who attended the ses- sion learned about new technology and data that UC researchers are employing,
including soil moisture sensors and data from the California Irrigation Management Information System. San Diego County’s avocado produc- tion is managed primarily by small farms. Montazar said this adds a level of com- plexity to water management because there is a greater emphasis on irrigation tools and strategies being user-friendly and cost-efficient. “We don’t know the future,” said Montazar, who pointed to the Colorado River water cri- sis and depleted reservoirs that could even- tually affect San Diego County’s water sup- plies. (See related stories on Pages 2 and 3.) Water has always been a challenge for San Diego County. In the 1970s, California’s water program paved a way for an additional 98,000 acres of agricultural land. Today, the county has 250,000 acres and $1.8 billion in agricultural production. According to a 1970 study analyzing av- ocado production in San Diego County, water costs “averaged 3½ acre-feet per acre at $60 an acre-foot,” which came with the assumption that costs would remain rel- atively low and affordable for a long time. That is no longer the case. Beginning in 2023, the San Diego County Water Authority will raise the rates for water, prompting growers to invest in more effi- cient irrigation practices. There are no loopholes or short cuts
Avocado acreage in San Diego County has declined sig- nificantly. Some farmers blame the reduction on costs to irrigate the crop.
when it comes to irrigation because irri- gation is the key to tree health, said Ben Faber, UCCE subtropical crops advisor for Ventura and Santa Barbara counties. Faber pointed out that tree health is how growers stay in business. “You can mess up your fertilization pro- gram, and you can mess up your pesticide program, but if you mess up your irrigation program, you’re out of business,” he said. Faber said efficient irrigation requires a strong grasp on salt management. “We import water that has a lot of salt in it. So, you’ve got to figure out how to put the right amount of water on the root zone with- out causing root health problems,” he said. This process requires meticulous care, as anything that gets below the root
zone can cause groundwater contami- nation, for which growers do not want to be responsible. While the latest irrigation technology such as smart controllers could help grow- ers, Faber said training and educating farm managers should be a priority. As Faber put it, managing irrigation should be “like brushing your teeth,” which he said growers do naturally and compe- tently. But researchers caution that an overirrigated tree looks just like an under- irrigated tree, and growers must recognize the difference and plan accordingly. (This report was adapted from an article originally published by University of California Agriculture and Natural Resources.)
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November 9, 2022 Ag Alert 13
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