Instruments measure high frequency temperature and net radiation above the experimental sites at avocado orchards across Southern California.
New research helps avocado growers save water, cut costs harming their crops.
A study led by irrigation expert Ali Montazar is helping Southern California avocado growers use water more efficient- ly, potentially saving thousands of dollars annually while preserving one of the re- gion’s most valuable crops. Montazar, a University
Noting that as much as 50% of an avo- cado grower’s production costs go to irri- gation, Montazar set out to develop more reliable crop coefficients for avocados, based on real-world data. “This is huge. We have never had a project like this conducted for avoca- dos in California,” Spann said. “The crop coefficient we used previously was de- veloped out of a salinity project done 20- plus years ago.” Montazar said he is developing crop-co- efficient curves and user-friendly tools for growers. Crop coefficients take into account a variety of environmental and plant factors, such as growing region, crop canopy, topography, and soil type and condition, to determine more precisely the optimal amount of water to apply. The newly developed crop coefficients will be plugged into an existing irrigation calculator and have also been used to veri- fy the satellite data-based models available through OpenET, an online platform that uses satellites or remote sensing to esti- mate on-farm water use. “Growers can rely on these numbers. They’re based on real-world data from actual orchards,” Montazar said. “We’re giving them the tools to make informed, cost-saving decisions.” Growers, eager to adopt new water-sav- ing strategies, have welcomed the findings. “The avocado community has been in- credibly supportive,” Montazar said. “They know water efficiency is not just import- ant—it’s essential.” Montazar plans follow-up research to examine how improved irrigation practic- es affect avocado yield. The project was supported by the California Department of Food and Agriculture Specialty Crop Block Grant Program. Access the paper at www. sciencedirect.com/science/article/pii/ S0378377425001957.
of California Cooperative Extension adviser, spent three years collecting data from 12 commer- cial orchards across
IRRIGATION
Riverside, San Diego, Orange and Ventura counties. Facing steep slopes and rugged terrain, he used cutting-edge remote sens- ing and field-based sensors to calculate precise crop coefficients—numbers that help growers determine how much water avocados truly need. “Water for avocado is the single biggest input, dollarwise, that growers have. It tops harvest costs; it tops fertilizer costs,” said Tim Spann, a California Avocado Commission research consultant and re- search program director. “Ensuring that growers are putting out irrigation at opti- mal rates goes directly to their bottom line.” The need for efficient and effective ir- rigation scheduling is especially acute in Southern California, where most of the state’s avocados are grown. “This region is under pressure due to a variety of water issues, facing uncertain water supplies, mandatory reductions in water use and rising costs of water,” said Montazar, noting that San Diego County has some of the highest water costs in the nation. California leads the nation in avocado production, with the crop valued at more than $523 million in 2024. However, grow- ers in Southern California face rising water costs and strict usage limits. Montazar’s findings showed that previ- ous water estimates were often too high, leading to unnecessary irrigation. In many cases, Spann said, growers can cut back water use by at least 10% without
May 21, 2025 Ag Alert 17
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