Vineyard Site Selection
Water Requirements and Quality
With the high cost of vineyard establishment and maintenance an adequate supply of good quality water is a must in when selecting the vineyard site.
Water Requirements
While climate and humidity play important roles as well as the soil, a typical grape vine needs 25 to 35 inches (635 –890mm) of water a year, occurring during the spring and summer months of the growing season, to avoid stress. If much of the vines’ water needs are met by rainfall, the distribution rather than the total amount of rainfall is important. Too much or too little water at a crucial time is deleterious to wine quality. Excess vine vigor resulting from rain before, but even more crucially after véraison can damage fruit quality by causing increased disease and berry size and impede fruit ripening.
What Determines Grapevine Water Requirements
Grapevine water requirements are influenced by climate and weather (temperature, rainfall, humidity, and sunlight), vine characteristics (age, variety, canopy size, and rootstock), soil properties (type, depth, and water-holding capacity), and vineyard management practices (planting density, trellis system, and use of cover crops). These factors determine the plant’s water needs and the amount of water available in the soil.
Water Quality
The well water should be tested to determine its suitability for grape production. A sample should be analyzed for pH, EC, carbonates (CO32-), bicarbonates (HCO3¯), sodium (Na2⁺), chloride (Cl¯), calcium (Ca2⁺), magnesium (Mg2⁺), potassium (K⁺), nitrate-nitrogen (NO3¯), and sulfate (SO42¯). Hard water that contains high levels of calcium and/or magnesium can cause white film deposits such as calcium carbonate in pipes. Irrigation water with high levels of salt (such as chloride, sodium, boron, and bicarbonates) may prove unsuitable for grapevines.
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