A study was conducted to determine the water use or vineyard evapotranspiration (ET) of Chardonnay grapevines subsequent to vineyard establishment. ET is the combined loss of water by evaporation from the soil and transpiration by the vine. The experimental vineyard is located in the Carneros District of Napa Valley. In addition, the vines were grafted onto two different rootstocks (110R and 5C) to determine if there are differences in water use between them. Lastly, five irrigation treatments were imposed to determine the effects of both under- and over-irrigation on vine physiology and growth and wine quality. Vine water use was determined by measuring soil water depletion and the addition of water during an irrigation. Soil water content was measured with a neutron probe at eight sites throughout the vineyard, four sites per rootstock. Vineyard water use in 1997 at full ET (i.e. water applications equal to vine water use) was approximately 470 mm (18.5 inches). Deficit irrigation of vines resulted in the depletion of soil water, the amount dependent upon water application amounts. There has been no difference in water use between the two rootstocks. Water applications less than full ET resulted in more negative leaf water potentials and lower stomatal conductance and photosynthesis. The percent reduction was a function of the amount of water applied. There were significant reductions in berry size for vines that were deficit irrigated in 1997. There have been no differences among irrigation treatments with regard to juice pH. Titratable acidity increased with increasing water applications. There were minor differences in berry composition among the rootstocks in 1997; however, there were no significant interactions among rootstocks and irrigation treatments. Experimental wines made in 1997 are currently being analyzed.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF1997-10-18 12:55:342017-10-18 12:56:35Water Use and Effects of Deficit Irrigation on Chardonnay Grapevines Grown in the