Issue link: https://www.e-digitaleditions.com/i/1390079
WATER USE ALMOND ORCHARD 2025 GOAL "A lot of what we do is basic research, and that is foundational to get us where we are today," Kustas said. "Now to see it through, where it has real utility for growers, that is the ultimate goal of the USDA's Agricultural Research Service." Predicting yield to determine where to irrigate Making informed irrigation decisions requires understanding what impact each of those decisions will have on yield. Building an irrigation portfolio strategy on yield prediction, therefore, reaps two important benefits: It creates a model for growers to use for their own management decisions, and it provides each of the researchers in the portfolio with one of the most important data points: how will this approach impact yield? Directing a large team of researchers within the strategic irrigation portfolio is Dr. Patrick Brown, professor in the Department of Plant Sciences at UC Davis. Under his leadership, multiple projects are leveraging individual tree harvesting, artificial intelligence, remote sensing, deep learning and other cutting-edge approaches to quantify tree-level yield parameters. To get this right, the data needs to be at the individual tree level to account for in-field variability. At each of the three collaborator sites the team will collect individual tree yield data that will allow them to not only power the yield prediction model, but also to integrate their efforts with the research projects of Kustas, McElrone, and Torres. "It's uncommon for all of us researchers to work collaboratively together, and I've got to give kudos to the Almond Board for thinking about it in this way," says Brown. "I think the portfolio approach is a fantastic idea, and it's the way science should be done." From growers, Brown and his team have learned how they predict yield in their own orchards. Building on these factors, researchers will use satellite imagery, drones, and ground-based devices to refine a model for yield prediction. Brown hopes they will be able to reliably predict yield within 200 pounds per acre as early in the growing season as April so that growers can use this information to make management decisions during the growing season. Most of the previous research that's been done on irrigation has been in the vein of determining how much water the tree would use if given all the water it wanted. "What we really need to get to is: what should the tree use if we wanted to use our water most efficiently," Brown said, "and that is not something we have a lot of information on." Adjusting irrigation to optimize for potential yield The missing piece of the puzzle Brown referenced is the decision of what to do once the grower has their yield prediction in-hand: T-REX will make it easier for growers to know when trees are stressed and how much they are transpiring. The team Brown is leading will give growers the tools to accurately measure yield early enough in the season to maximize water efficiency. These initiatives go a long way but fall just short of informing a grower of exactly what actions to take. During the kickoff meeting of the strategic irrigation portfolio, one question that Saa posted as part of ABC strategic plan generated a great deal of discussion among the researchers in attendance: can yield drive irrigation and not the other way around? In other words, can an algorithm be developed that analyzes actual ET, potential yield, and other factors to specifically inform an optimal decision on when, where, and how much to irrigate? Maciej Zwieniecki, Ph.D., professor in the Department of Plant Sciences at UC Davis, is researching this exact question. The former Sargent Fellow at Harvard University has already analyzed the connection between carbohydrate content in the tree and future yield. Now, he'll be combining that model with the research highlighted to consider how irrigation should be adjusted with potential yield changes, and what impact that has on both the short-term and the long-term tree performance. "If we know that certain conditions (i.e. poor fruit set due to adverse weather conditions) lower the potential yield early in the season, our yield cannot go back up from there no matter how much water we apply," said Zwieniecki. "So, what would happen to the crop if we reduce the water application to match that lower potential yield?" Finding the answer to this question is the reason Dr. Zwieniecki's project is an important part of the strategic irrigation portfolio. Moving from research to reality This strategic approach to research maximizes growers' return on investment and makes sure that the research is complete enough to be actionable. Still, Saa believes one more stakeholder group is necessary to ensure the latest information on water use efficiency is incorporated into the daily operations of almond growers: agricultural technology providers. "There is no question that ABC can play a catalytic role to help with research outputs among tech companies," said Saa. "We want to make sure that growers realize the benefits of this research, and ag tech companies are an important part of that." To access the latest information on irrigation management that's informed by 40 years of research, growers are encouraged to visit Almonds.com/Irrigation and download the Almond Irrigation Improvement Continuum. 1 2 Continued from page 10 11