Articles
USING THE HEAT PULSE “TMAX” PROCEDURE TO ESTIMATE GRAPEVINE WATER USE IN A HUMID CLIMATE
Article number
846_18
Pages
177 – 184
Language
English
Abstract
Vine water use was measured in a Vitis vinifera cv.
Riesling vineyard located in New York.
Vines were fully irrigated, non-stressed, and were trained via vertical shoot positioning with a narrow canopy.
Light interception was about 30% of the incident light during the sunlit hours.
Six vines were instrumented with heat-pulse sap flow gauges using the Tmax procedure.
Sap flow values were calibrated for short periods with whole canopy transpiration measurements via gas exchange.
Measurements started late in June, when the canopy filled the trellis, and continued until October.
Five out of six heat pulse gauges clearly underestimated canopy transpiration.
Only one vine gave realistic values.
When uncorrected deviations from the actual values were considerable and varied from vine to vine.
This suggests that there was not a systematic error in sap flow readings but rather a seemingly random deviation from the actual values.
This was probably due to differences between plants in the location of the probes with respect to the portion of the trunks sapwood that transport the majority of the water.
Vine water use during most of the summer days was between 1.0 to 2.0 mm day-1, giving weekly totals of 7 to 15 mm in cool and hot weeks.
The basal vine crop coefficient (Kcb – basal referring to vine water use only) varied somewhat between days but it was relatively stable over the season.
Averaged over the entire experimental period Kcb was 0.49, about 20% higher than previously published values.
Riesling vineyard located in New York.
Vines were fully irrigated, non-stressed, and were trained via vertical shoot positioning with a narrow canopy.
Light interception was about 30% of the incident light during the sunlit hours.
Six vines were instrumented with heat-pulse sap flow gauges using the Tmax procedure.
Sap flow values were calibrated for short periods with whole canopy transpiration measurements via gas exchange.
Measurements started late in June, when the canopy filled the trellis, and continued until October.
Five out of six heat pulse gauges clearly underestimated canopy transpiration.
Only one vine gave realistic values.
When uncorrected deviations from the actual values were considerable and varied from vine to vine.
This suggests that there was not a systematic error in sap flow readings but rather a seemingly random deviation from the actual values.
This was probably due to differences between plants in the location of the probes with respect to the portion of the trunks sapwood that transport the majority of the water.
Vine water use during most of the summer days was between 1.0 to 2.0 mm day-1, giving weekly totals of 7 to 15 mm in cool and hot weeks.
The basal vine crop coefficient (Kcb – basal referring to vine water use only) varied somewhat between days but it was relatively stable over the season.
Averaged over the entire experimental period Kcb was 0.49, about 20% higher than previously published values.
Publication
Authors
D.S. Intrigliolo, A.N. Lakso, R.M. Piccioni
Keywords
crop coefficient, irrigation, sap flow, transpiration, Vitis vinifera
Online Articles (44)