Precision Viticulture: Inputs or Outputs?

At the ASEV-NGRA Precision Viticulture Symposium, held virtually on June 21, 2021, two keynote presentations bookended the day. Rob Bramley, a Senior Principal Research Scientist at CSIRO (Commonwealth Scientific and Industrial Research Organisation) in Australia, opened the event with remarks on “Precision Viticulture and Beyond – Digital Approaches to Winegrowing.” (He noted that “Winegrowing, to me, is the culmination of grapegrowing and winemaking,” which has been his particular focus. “Hopefully, most of what I have to say will apply to the juice, table grapes and dried fruit sectors, as well.”) And Nick Dokoozlian, Vice President of Winegrowing Research at E. & J. Gallo Winery and NGRA’s Research Chair, closed the day with a keynote presentation entitled, “The Promise and Challenge of Precision Viticulture.”

Widely considered the father of precision viticulture, Rob set the stage for the sessions on pests and diseases, crop estimation and decision support systems, vine management and grower best practices that followed. The basic promise of precision agriculture, he said, stems from the premise that land is variable, and understanding that variability and its limitations to production is valuable. Precision ag works on a cyclical system of 1) observation about variability, 2) evaluation and interpretation and 3) targeted management. Or “measure, model, manage,” as Terry Bates of Cornell University outlined in his talk, “Leveraging Sensor Information for Variable Rate Vineyard Management.”

But as Rob and other speakers observed, the focus of precision viticulture today is on the development of technology (“solutions looking for problems,” as he described), and growers are reluctant to invest in or adopt things they don’t fully understand. As NASA Harvest’s Alyssa Whitcraft said in her talk, “Down to Earth Data for Decision Support: NASA Harvest(ing) 50 Years of Global Agricultural Monitoring Research to Support Producers,” “We need to build up our evidence base” for what works. Rob illustrated, through the example of Australia’s grain sector, that the adoption of precision viticulture is greatly aided by a killer app. For grains, it was yield mapping. For the grape and wine sector, “it might not be yield maps,” Rob said. Perhaps it’s “AI-enabled Sensing for Crop Estimation,” as Mason Earles (UC Davis) discussed, or sensing/predicting fruit composition, both current topics of exploration in NGRA’s Research Committees.

Rob also introduced the idea of using precision viticulture on a regional level, to define and perhaps defend the distinctiveness of terroir. That idea of PV’s regional applications echoed through remarks on areawide efforts to control the spread of pests and diseases from Kent Daane (UC Berkeley), Chad Vargas (NewGen Vineyard Services) and Aaron Lange (LangeTwins Family Winery and Vineyards).

But the “main game” for precision viticulture in Australia, Rob said, has been on selective harvest and product streaming of fruit. And that’s where the opening and closing keynotes diverged.

Today, Nick said, we’re in the early stages with precision practices. “We’re at a point where we’re describing what happened” over the course of the growing season or what he calls “descriptive analytics.” That current state of the art is “at the low end of value,” delivering relatively little return, which speaks to the barriers to adoption and investment described above.

He believes that the promise of precision viticulture is “prescriptive analytics,” or managing or controlling what happens in the field. We need to progress from managing vineyards in hindsight to achieving foresight, or “real-time, on-the-go actuation,” moving “beyond what Mother Nature gave us…to drive to the desired quality tier or yield.” But we’re a long way away from that vision, he said.

Returning to the killer app concept as Rob described, Nick noted that yield mapping, particularly as it relates to vineyard variability, has been a primary driver of Gallo’s adoption of precision viticulture. And what’s driving vineyard variation is soil moisture. He described long-running research in conjunction with USDA-ARS Hydrology and Remote Sensing Lab and others to harness remote sensing and big data to enable variable rate precision irrigation. “There’s no question that remote sensing has become perhaps our most powerful tool in terms of increasing our ability to estimate the amount and apply water accurately.” But the differences in resolution of the various sensors, the “huge challenge” of occlusion in the fruit zone preventing sensors from collecting accurate images and the difficulty in manipulating the data hampers the ability to model vineyard information and drive toward action.

At the end of the day, the symposium illustrated Rob Bramley’s statement: “In a variable landscape (like vineyards), uniform management is a sub-optimal strategy.” Whether a precision viticulture program focuses on variable-rate inputs, as with irrigation, nutrition, sprays, etc., to minimize vineyard variability, reduce costs and improve quality and efficiency, or on outputs to enable selective harvest and product streaming, there’s opportunity in farming with precision. If you’re unsure what technologies you need or how to use it, the symposium agenda can serve as a roster of experts to ask. As Terry Bates, Aaron Lange and others noted, the important thing is to just get started.

Editor’s Note: If you registered for the ASEV-NGRA Precision Viticulture Symposium, use your registration credentials (badge number and password) to view all the presentations now through July 16, 2021. Note that the live sessions held that afternoon are viewable as part of the entire afternoon recording. For example, the grower panel begins at the 1:41 mark and Nick’s talk starts at the 2:29 mark.

The ASEV-NGRA Precision Viticulture Symposium was generously funded by a grant from the USDA-NIFA Agriculture and Food Research Initiative.