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G r AP e G ro WING Time Needed to Apply Water Hours needed to apply an acre inch of water to a vineyard with 1 gallon per hour emitters installed for each vine: Vine spacing in feet (Row width by vine distance in row) 8 x 5 8 x 6 9 x 5 9 x 6 10 x 5 10 x 6 8 x 12 Vines per acre and gallons used per hour (Fitted with 1gph emitter per vine) 1,089 907 968 806 871 726 453 Number of hours to apply an acre inch 25 30 28 34 31 37 60 An acre foot is the amount of water that covers an acre of ground, which is 325,851 gallons. Evapotranspiration is usually measured in fractions of an inch per day, and inches per week, month or year. An acre inch= 27,154 gallons. water precisely beneath the vines and avoid wetting the fruit dur- ing the growing season. Irrigation water can be applied right up un- til harvest. In the Okanagan Valley, Ag Canada researcher Dr. Pat Bowen has shown that an added benefit of drip irrigation is that it promotes ripening up to two weeks earlier due to warmer tempera- tures on the vineyard floor. In northern climates with shorter growing seasons, this is a definite advantage. Drip irrigation Drip irrigation is now the most common way to irrigate vine- yards. It can be very uniform and efficient since it operates under low pressure, and the emitters are very reliable as long as filtra- tion and water quality are both good. Water losses from runoff or evaporation are very small. Drip irrigation allows considerable flexibility in scheduling, stretches limited water supplies and re- quires less energy to deliver water compared to sprinklers (since volume, pressure and flow requirements are less). Most systems IDL_Dir11 11/18/10 4:21 PM Page 1 Iván D.Lessner Process Solutions Inc. Process & Product Development Alcoholic & Non Alcoholic Beverage Industry Equipment Sales IDL ■ R. WAGNER: Rapid SO2, TA ■ ERBSLOEH: Fining & Treatment Agents, Yeasts, Enzymes, CelluFluxx (D.E. Replacement) ■ TRUST: Quality Hungarian Oak Barrels & Chips ■ EMD: Reflectoquant Analyzer & Kits 1164 Lee Street, White Rock, B.C. V4B 4P4 Canada Phone: (604) 538-2713 Fax: (604) 538-4517 www.idlconsulting.com 82 Wines & Vines JUne 2011 are designed to deliver about 1 gallon of water per vine per hour, and this is usually done with one or two emitters. Emitters come in many different styles and usually attach to black polyvinyl drip hoses. You can also purchase drip hose with built-in emitters, which can save considerable labor during installation. Irrigation scheduling Regardless of the irrigation system that you choose, you will need to know when to start irrigating. Water is stored in the soil from rain either before or during the growing season. The rest of the vine water needs must be provided by irrigation. Vine water use is dependent on the weather. Soil moisture is removed in part by evaporation, which is greatest when the weather is hot, sunny and dry. The vines draw moisture from the soil with their roots and emit water vapor from their leaves by the process of transpira- tion. Irrigation scientists call the combination of water removal from the soil by these two processes evapotranspiration (ET). This is calculated using environmental weather data and is expressed in inches or millimeters. You can source ET information online, through the newspaper in some communities or with your own weather station in the vineyard. Since ET data is expressed as inches or millimeters of water per day, you will also need to know how much water you apply to your vineyard in an hour so that you can figure out how many inches of water you are applying per acre per hour. This will be important when you calculate how long to run your system to replace the water depleted from the soil profile due to ET. Ulti- mately, most calculations summarize water use per vine in gallons or liters. For each vine this may range from 30 gallons per year to more than 300 gallons per year depending on the vineyard, vine- yard design and vineyard location. How you apply irrigation water can greatly affect the growth of the vine and the quality of the fruit. Research done in many ir- rigated regions around the world has definitely changed irrigation strategies during the past two decades as a way to conserve water and energy while improving fruit quality. Regulated deficit irrigation Regulated deficit irrigation (RDI) is a strategy in which irrigation is minimized compared to fully watered vines. RDI is not used