TECH NOTE 1 | FEB 2020 Clos de la Tech Clos de la Tech’s winery in Woodside, California makes premium Pinot Noir using state-of-the-art WaterBit technology

TJ’s “Living Lab” So, TJ turned to soil moisture sensors as a way to accurately Silicon Valley entrepreneur, TJ Rodgers, is WaterBit’s Chairman. measure soil volumetric water content (VWC) in the vine rootzone He has created a Living Lab at his Clos de la Tech winery to further his goal of developing and deploying automated watering. in Woodside, California, where he tests the latest irrigation In 2016, the VWC sensors available on the market did accurately technologies by measuring their impact on , water usage measure soil VWC, but were too expensive to deploy en masse in and quality. At WaterBit, we pore over the experimental many small blocks, so TJ launched a project to create a details to help shape our Autonomous Irrigation Solution low-cost, VWC sensor—this was the spark that launched WaterBit. (AIS) product roadmap. We invite you to visit our San Jose headquarters to see the produc tion version of our AIS in action. TJ also worked with the WaterBit team to develop a highly reliable, compact, solar-powered electronic system (no batteries!) that Background paired with a VWC probe. The purpose of this system was to TJ Rodgers founded Cypress Semiconductor in 1982 and led measure soil VWC at various depths and send this data to the the organization for 34 years. Cypress Semiconductor pushed cloud, where it could be analyzed and used to control irrigation. the envelope in developing and bringing to market cutting edge This device has evolved into what is now the WaterBit CarbonTM, silicon chip solutions like the Programmable System on a Chip a cost-effective irrigation controller with thousands of units in (PSoC), and even whole new companies like solar industry leader the field. TJ has used a VWC-based watering solution in his own SunPower, which was a Cypress project until it was spun out as winegrape production for three years. This solution waters his a separate company. TJ also owns three and has been vineyard automatically, block by block, by turning on the block making wine for over 20 years under the Clos de la Tech brand. watering valves when the VWC of the soil in a block falls to a pre His passion for applying technology to led to his defined “trigger level.” As illustrated in the next graph, the solution investment in WaterBit, whose automated irrigation solution is works like a thermostat, which heats whenever a room cools off. deployed in TJ’s vineyards.

TJ has been experimenting with automated irrigation technologies to increase crop quality while simultaneously reducing water use. TJ’s experiments have helped WaterBit improve its products and are shaping our AIS product roadmap. Let’s take a look at the results of some of his experiments.

The Quest to Cost-Effectively Measure Water at a Micro-Level (2016) TJ is a member of the Board of Advisors of the UC Davis School of and Enology. He worked with Department Head, Dr. David Block, in a quest to invent a reliable, cost-effective method to directly measure the water needs of vineyards down to the single vine and deliver the right amount of water at the right time to each vine. He initially focused on getting baseline data by measuring Leaf Water Potential (LWP), a direct vine measurement of water need, on vines in small, quarter-acre Figure 1. Autonomous Irrigation Solution (AIS) Watering. The black curve shows percent soil moisture (VWC) at a depth of 2”. In this case, a watering is triggered vineyard blocks. LWP measurement is very labor intensive and, whenever VWC drops to the programmed 39% trigger level. Note these short unfortunately, after 10 years of searching, he has been unable waterings barely penetrate to the 10” VWC (red) and do not reach the 14”-22” to find a good, continuous, low cost automatic LWP sensor. The VWC probes. This shows that water loss from percolation through the root zone problem is that the sensor needs to be inserted into the xylem has been eliminated. (water-carrying tissue of the vine), causing a wound that changes measurements over time. Early Results (2017) Validating 2017 Results Beginning in 2017, TJ conducted a variety of production experi- TJ usually uses any new equipment in his home vineyard ments at Clos de la Tech using VWC probes to measure soil for a full year before he orders more equipment to replicate VWC and its impact on vine water usage and yield. As stated by favorable results for a second year. Only then, does he install Rodgers: “The purpose of the experiments is to compare the use the new equipment in his two larger production vineyards in of an Autonomous Irrigation Solution for AIS watering (defined as the Santa Cruz Mountains. The 2018 AIS watering results again using VWC soil moisture measurements to automatically control demonstrated exceptional water savings vs. the control blocks. the block water valves) to our standard practice of LWP watering, which uses Leaf Water Potential (LWP) measurements and Rodgers stated: “While water usage dramatically decreased in manually controlled block water valves.” both 2017 and 2018 by using the AIS to achieve record-low water use, you might ask, did it impact quality? Both the quality (measured at ) and wine quality (blind tasting one year later) were equivalent, and all of the experimental barrels qualified “ WaterBit doesn’t overwater, it doesn’t underwater. It gives what the plants tell it to give.” for incorporation in our reserve wine ($130 per bottle).”

TJ Rodgers, He also reported that in addition to the excellent production Owner of Clos de la Tech & WaterBit Chairman of the Board results, AIS caused him to make a major discovery on a newly planted block.

The results shown in Table 1 were quite remarkable. In the AIS “The automated solution also detected a severe watering experimental blocks, TJ obtained comparable crop yield and problem in a new buried emitter drip system that was supposed quality, while cutting vineyard water usage by 38%-52%. This to be more water efficient by eliminating surface evaporation. Up was compared to the control blocks, in which manual irrigations to 90% of the applied water in certain micro-blocks percolated were made in response to leaf water potential measurements. through the root zone and was wasted. The drip emitters were buried eight inches deep in a block with a very shallow rootzone, TJ also reported excellent quality: “The total season irrigation leaving only 12 inches of rootzone below the buried emitters. The (TSI) for 2017 in the AIS-watered blocks was only 0.20 inches emitter watering plume penetrated the rootzone in 30 minutes to 0.46 inches, record low numbers for the vineyard, which was and any water added after that was lost. The quick and simple planted in 1994. The AIS blocks were fermented and barrel aged solution to the problem was to change the irrigation time from two separately. Both crop yield and blind tasting results showed hours to thirty minutes something that cannot be done practically quality comparable to the control blocks, despite the water with humans turning manual valves on and off.” savings. I hypothesized that the extra water used in the control irrigations probably percolated through the rootzones, doing no Moving Forward good at all.” (That hypothesis was verified in 2018.) With these promising early results, TJ continues to search for reliable and practical irrigation methods to use at Clos de la Tech. 2017 Experiment Name House (H) House (H) Winery (W) Winery (W) Bottom (B) Bottom (B) Cont 1 Exp 2 Cont 2 Exp 2 Cont 3 Exp 3 This year, he is installing WaterBit’s new MicroBlock Valve™, and Experiment Variables LWP AIS LWP AIS LWP AIS H2O/watering (pgv/w) 2.0 0.5 2.0 0.5 2.0 1.0 he plans to implement WaterBit’s enhanced monitoring controls Yield (tons per acre) 3.10 2.82 3.93 3.78 2.29 2.33 vs Control 91.0% 96.2% 101.7% to measure irrigation flow and pressure to automatically validate WUE1: Gal Water/# 1.82 0.95 2.64 1.65 4.02 2.42 TSI (inches)2 0.42 0.20 0.77 0.46 0.68 0.42 that the appropriate watering recipe was applied to each block on vs Control (% savings) 52% 40% 38% every watering. We look forward to reporting on those results in a 1. Water Use Efficiency. 2. Total Seasonal Irrigation: 10,000 gallons per acre per year (gpa/yr) = 0.368”/yr = 9.35 mm/yr. later Tech Note.

Table 1. 2017 Woodside Vineyard water use and crop yield. About WaterBit TJ summarized the 2017 results: “The AIS demonstrated WaterBit’s precision irrigation solution lets growers measure exceptional water use efficiency (WUE) as low as 0.95 gallons of soil moisture and execute irrigation remotely, and at a level of irrigation water per pound of crop (gal/#), using 5,346 gallons granularity and accuracy that would otherwise not be possible. per acre per year (gpa/yr), or 0.20” of irrigation water, to produce WaterBit translates technology into tangible value for growers a crop of 2.8 tons per acre (tpa). The lowest efficiency of three by improving yields and crop consistency, and optimizing water AIS experimental blocks still had excellent performance, using and labor. Learn more at www.waterbit.com. 12,474 gpa/yr (0.46”) to produce a crop yielding 3.8 tpa at a WUE of 1.65 gallons per pound of crop.”

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