WATER USE AND CANOPY CONDUCTANCE OF THOMPSON SEEDLESS GRAPEVINES GROWN IN THE SAN JOAQUIN VALLEY OF CALIFORNIA

Two Thompson Seedless grapevines were planted in a weighing lysimeter at a field station near Fresno, California, in 1987. The lysimeter’s soil container was 2 x 4 x 2 m (width x length x depth) and sat upon a scale.
The lysimeter was fully automated and irrigated the vines whenever they used 2 mm of water.
The vines were head trained and cane pruned the trellis system consisted of a 0.6 m crossarm, with fruiting wires at either end, on top of a 2.13 m stake.
Since 1987 diurnal, daily and seasonal water use has been determined.
The flux of water vapor by the vines was determined by using information collected by the lysimeter.
Total vine conductance (g_ctot) to water vapor was determined using the following equation: g_ctot = EP/V, where E equals vine evapotranspiration (determined with the lysimeter), P equals barometric pressure and V equals canopy-to-air vapor pressure difference.
Canopy conductance (g_c) was determined by subtracting the aerodynamic conductance from g_ctot. Canopy conductance was linearly related to photon flux density on a diurnal basis.
Canopy conductance was also linearly related to the composite variable; photon flux density divided by leaf to air vapor pressure difference.
The lysimeter has been useful in providing basic information on the effects of the environments on water relations and water use of non-stressed grapevines grown in the San Joaquin Valley

V International Symposium on Grapevine Physiology

Larry E. Williams

Vitis vinifera L., evapotranspiration, weighing lysimeter

https://doi.org/10.17660/ActaHortic.2000.526.12