The relationship between grapevine sap flow, ETo and effective area of shade

Abstract

Accurate prediction of potential grapevine transpiration from reference crop evapotranspiration (ETo) and a basal crop coefficient (K cb) is necessary to improve water use efficiency. Sap flow (SF) was used in this study to estimate transpiration. The relationship between SF and ETo adjusted by effective area of shade (EAS) for Shiraz grapevines (Vitis vinifera) was investigated during two seasons at a vineyard near Tatura, Australia. SF was measured using the Tmax method. Sap flow sensors (Tranzflo, Palmerston North, New Zealand) were installed in four vines at each of nine locations approximately 28 days after budburst (DABB) and were removed just prior to harvest. Fractional canopy photos..