Use Case

Early Results (2017) Beginning in 2017, TJ conducted a variety of production experi- ments at Clos de la Tech using VWC probes to measure soil VWC and its impact on vine water usage and yield. As stated by Rodgers: "The purpose of the experiments is to compare the use of an Autonomous Irrigation Solution for AIS watering (defined as using VWC soil moisture measurements to automatically control the block water valves) to our standard practice of LWP watering, which uses Leaf Water Potential (LWP) measurements and manually controlled block water valves." The results shown in Table 1 were quite remarkable. In the AIS experimental blocks, TJ obtained comparable crop yield and quality, while cutting vineyard water usage by 38%-52%. This was compared to the control blocks, in which manual irrigations were made in response to leaf water potential measurements. TJ also reported excellent quality: "The total season irrigation (TSI) for 2017 in the AIS-watered blocks was only 0.20 inches to 0.46 inches, record low numbers for the vineyard, which was planted in 1994. The AIS blocks were fermented and barrel aged separately. Both crop yield and blind tasting results showed quality comparable to the control blocks, despite the water savings. I hypothesized that the extra water used in the control irrigations probably percolated through the rootzones, doing no good at all." (That hypothesis was verified in 2018.) Table 1. 2017 Woodside Vineyard water use and crop yield. TJ summarized the 2017 results: "The AIS demonstrated exceptional water use efficiency (WUE) as low as 0.95 gallons of irrigation water per pound of crop (gal/#), using 5,346 gallons per acre per year (gpa/yr), or 0.20" of irrigation water, to produce a crop of 2.8 tons per acre (tpa). The lowest efficiency of three AIS experimental blocks still had excellent performance, using 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." Validating 2017 Results TJ usually uses any new equipment in his home vineyard for a full year before he orders more equipment to replicate favorable results for a second year. Only then, does he install the new equipment in his two larger production vineyards in the Santa Cruz Mountains. The 2018 AIS watering results again demonstrated exceptional water savings vs. the control blocks. Rodgers stated: "While water usage dramatically decreased in both 2017 and 2018 by using the AIS to achieve record-low water use, you might ask, did it impact quality? Both the grape quality (measured at harvest) and wine quality (blind tasting one year later) were equivalent, and all of the experimental barrels qualified for incorporation in our reserve wine ($130 per bottle)." He also reported that in addition to the excellent production results, AIS caused him to make a major discovery on a newly planted block. "The automated solution also detected a severe watering problem in a new buried emitter drip system that was supposed to be more water efficient by eliminating surface evaporation. Up to 90% of the applied water in certain micro-blocks percolated through the root zone and was wasted. The drip emitters were buried eight inches deep in a block with a very shallow rootzone, leaving only 12 inches of rootzone below the buried emitters. The emitter watering plume penetrated the rootzone in 30 minutes and any water added after that was lost. The quick and simple solution to the problem was to change the irrigation time from two hours to thirty minutes something that cannot be done practically with humans turning manual valves on and off." Moving Forward With these promising early results, TJ continues to search for reliable and practical irrigation methods to use at Clos de la Tech. This year, he is installing WaterBit's new MicroBlock Valve ™ , and he plans to implement WaterBit's enhanced monitoring controls to measure irrigation flow and pressure to automatically validate that the appropriate watering recipe was applied to each block on every watering. We look forward to reporting on those results in a later Tech Note. About WaterBit WaterBit's precision irrigation solution lets growers measure soil moisture and execute irrigation remotely, and at a level of granularity and accuracy that would otherwise not be possible. WaterBit translates technology into tangible value for growers by improving yields and crop consistency, and optimizing water and labor. Learn more at www.waterbit.com. WaterBit, Inc | 5870 Hellyer Avenue, San Jose, CA 95138 | 1.408.618.6900 | waterbit.com ©2020 WaterBit, Inc. All rights reserved. WaterBit and the WaterBit logo are trademarks or registered trademarks of WaterBit, Inc. in the USA and other countries. All other trademarks are the property of their respective companies. Information is subject to change without notice. " WaterBit doesn't overwater, it doesn't underwater. It gives what the plants tell it to give." TJ Rodgers, Owner of Clos de la Tech & WaterBit Chairman of the Board 2017 Experiment Name House (H) Cont 1 House (H) Exp 2 Winery (W) Cont 2 Winery (W) Exp 2 Bottom (B) Cont 3 Bottom (B) Exp 3 Experiment Variables LWP AIS LWP AIS LWP AIS H2O/watering (pgv/w) 2.0 0.5 2.0 0.5 2.0 1.0 Yield (tons per acre) 3.10 2.82 3.93 3.78 2.29 2.33 vs Control 91.0% 96.2% 101.7% WUE 1 : Gal Water/# Grapes 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 vs Control (% savings) 52% 40% 38% 1. Water Use Efficiency. 2. Total Seasonal Irrigation: 10,000 gallons per acre per year (gpa/yr) = 0.368"/yr = 9.35 mm/yr.

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