A SPECIAL GROWERS’ REPORT OF AG ALERT ® CALIFORNIA Trees & Vines
Plant moisture monitors help to optimize irrigation By Vicky Boyd A data logger records readings from a FloraPulse microtensiometer, which measures water potential in almond trees. The sensor is embedded directly into the tree’s woody tissue, providing contin- uous and accurate readings of water status. The data collected can be used to optimize irrigation practices and improve tree health.
In a previous two-year trial at the Kearney Agricultural Research and Extension Center near Parlier, University of California, Davis, plant science professor Ken Shackel compared pressure bomb midday stem water potential readings to those from FloraPulse, Phytech and another sensor no longer sold. The pressure bomb is considered the industry gold standard in assessing how much water stress a tree is experiencing. During the project funded by the Almond Board of California, Shackel found seasonal stress patterns were similar among all sensors with varying levels of correlation to tradi- tional pressure bomb readings. FloraPulse uses a microtensiometer installed in a tree scaffold a few millimeters below the bark into the xylem, or tissue that carries water from the roots to the canopy. By mea- suring how much suction is needed to pull water from the soil, the device reports stem water potential as a negative number. A data logger mounted nearby records plant water status and irrigation system opera- tion, sending the information to the cloud. While pressure bombing is labor-intensive and involves bagging tree leaves and then applying pressure to the bagged leaves, FloraPulse provides stem water potential readings every 20 minutes directly to smartphones, said company founder and CEO Michael Santiago. The optional Pressure Bomb Express smartphone app converts the amount of stress the tree is experiencing, UC irrigation data and irrigation system information into area-specific recommendations, said Kaplan, who helped develop the app. He’s also a Chico-area prune See SENSORS, Page 7
As water and labor costs increase and availability decreases, a small but growing number of farmers have added plant moisture monitors to their toolbox to help fine- tune irrigation.
Two products on the market—FloraPulse and Phytech—use different technologies to provide real-time plant water status and reduce the manpower needed to monitor it.
As part of his Chico-based irrigation monitoring technology busi- ness, Pressure Bomb Express, Ryan Kaplan has installed FloraPulse in mostly almond orchards from as far north as the Sacramento Valley to Fresno. Grower interest definitely has increased, he said, and most of his customers have subscribed to the service to save water, improve yields or reduce labor costs. “No one has mentioned they’re doing it because of SGMA (Sustainable Groundwater Management Act), yet it’s a tool that could be super helpful if you’re being cut off from water,” Kaplan said. “I’m sure it will be brought up at some time.” Derek Sohnrey, who grows tree nuts and rice with his family near Orland, initially started using the pressure bomb to monitor tree water status and has since moved to FloraPulse in his almonds because of its labor savings and consistency of results. “It’s extremely helpful, especially when you’re trying to manage multiple crops,” he said. “Everybody’s trying to run small crews nowadays. From a time management side, (FloraPulse) is really nice.” The first year Sohnrey used the device, he compared his results to those of the pressure bomb and found them very close. He’s since stopped using the pressure bomb. IRRIGATION
6 Ag Alert May 21, 2025
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