ABSTRACT: A study is being conducted to determine the water use of Chardonnay grapevines grown in the Carneros District of Napa Valley during vineyard establishment. Vineyard water use was determined by measuring soil water content with a hydroprobe and measuring applied water and effective rainfall. The arrangement of access tubes at each site allowed us to quantify the amount of water within the soil profile. A decrease in soil water content would indicate that irrigation was not meeting the water requirements of the vines while an increase in soil water content would indicate that irrigation was greater than vineyard evapotranspiration (ET). The soil water content decreased from budbreak until the middle of September and remained constant after that. This would indicate that applied water was less than vineyard ET. Soil water supplied approximately 38%of the 316 mm (12.4 inches) of water used by the vines in that vineyard. Effective rainfall supplied 36%of the water used by the vines. The depth of water extraction from the soil profile extended to greater than 2.0 m (approximately 7 ft). Midday values of leaf water potential measured throughout the season were no more negative than -1.0 MPa (-10 bars) except when maximum, ambient temperatures were greater than 27°C (81°F) . The crop coefficient ranged from 0.2 to approximately 0.7, depending upon the time of year.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF1993-11-22 16:03:552017-11-22 16:05:05Water Requirements During and After Vineyard Establishment for Chardonnay Grapevines Grown in the Carneros District