Issue link: http://winesandvines.uberflip.com/i/279499
68 p r a c t i c a l w i n e r y & v i n e ya r d a p r i l 2 0 1 4 g r a p e g r o w i n g Your source for informative technical books. ORDER TODAY! www.PracticalWinery.com and click BOOKSHELF speaking in terms of distance-based calibration, and the unit of mea- sure can be any measurement of distance. If we are going to farm vineyards with different tractor row widths, then distance-based calibration makes much more sense than area-based calibration. There is more to this new math. It is also true that 1,000 linear feet of vine row is not always equal to 1,000 linear feet of vine row. Imagine a vertically shoot positioned vineyard in Sonoma County, Calif., in May and a vineyard on a quadrilateral trellis in Madera, Calif., in July. The canopy size is completely differ- ent! The 1,000 feet of vine row in Madera will have much more canopy to cover than the VSP vineyard in Sonoma. In addition to distance, we also need to adjust the calibration to compensate for the size of the canopy. The details of how to do distance-based calibration, including how to adjust for canopy size, are clearly explained in "Orchard & Vineyard Spraying Handbook" for Australia & New Zealand by Geoffrey O. Furness, which is available at the University of California, Davis, bookstore. According to Furness, both Austra- lia and New Zealand have switched from area-based calibration to distance-based calibration in their vineyards. If we want to make a similar transition it will not be simple, quick or easy. All of our pesticide labels are written with per-acre dose, and it is a violation of state and federal law to deviate from the label. In addition, our pesticide-use reporting procedures are all based on per-acre dose, as are spray rig calibration practices. Although we cannot make the transition immediately, I think it is important for each of us to begin to realize that, in modern California vineyards, the use of area-based calibration no longer makes rational sense. The transition to distance-based calibra- tion is inevitable and, in my opinion, the sooner the better. PWV ('Per Acre' Spray Dose Calibration, continued from page 58) Direct Sales Strategies Compliance Updates Industry Best Practices Hands-On Training Sessions Learn more and register at www.shipcompliant.com/events 9th Annual Direct Sales Conference May 8 & 9 Napa, CA