A new system developed by the University of California, Riverside aims to help farmers address overwatering by mapping soil moisture tree by tree, allowing for more precise irrigation. The research was led by Elia Scudiero, associate professor of precision agriculture and Director of UCR’s Center for Agriculture, Food, and the Environment (CAFE), according to an April 2 announcement.
The innovation comes at a time when water management is one of the biggest challenges facing agriculture in California and other dry regions. Many growers currently use expensive soil moisture sensors that are only installed in limited locations across large orchards. This often leaves them guessing about conditions for hundreds or thousands of trees.
“The information those sensors provide is very limited,” Scudiero said. “It really only tells you what’s happening in the immediate areas where they’re placed.”
The new robotic system moves through orchards measuring electrical conductivity—a property influenced by factors like soil moisture, salt, and clay content. By combining these readings with data from existing buried sensors, researchers can build statistical models that predict water content throughout an entire field. This creates a detailed picture of water distribution on a tree-by-tree basis.
“Using this method, growers will finally know how much water they have, and how much they need, and can water specific trees if they’re dry,” Scudiero said.
Proper moisture levels are critical for plant health; too little causes stress while too much deprives roots of oxygen. Enhanced precision could also help keep orchards viable as regulations tighten on groundwater use and costs rise. “If water becomes limited, farmers have two choices,” Scudiero said. “They can retire orchards, or they can find ways to produce the same crops using less water.”
Scudiero added that better-targeted watering may reduce fertilizer pollution since nutrients are less likely to wash below root zones into groundwater if only needed amounts are applied: “If you apply only the amount of water the plants actually need, you reduce the risk of washing those nutrients away from the roots of the crops and into the environment.”
Development began in 2019 through collaborations at CAFE between agricultural scientists and engineers. The team has filed a patent related to how their robot interacts with sensors without disturbing measurements. Research took place at UC Riverside’s Citrus Research Center & Agricultural Experiment Station; future work will focus on testing with commercial growers beyond university plots.
Moving forward will require machines capable of operating under varied conditions across different crop systems before private industry partners adapt it into commercial products.
For growers facing restricted access to water supplies in coming years—and for efforts at UC Riverside toward advancing precision agriculture—the technology offers hope for improved efficiency.
“More crop per drop!” Scudiero said.
