Articles
MATCHING IRRIGATION TO VINE WATER-REQUIREMENTS: LIMITATIONS OF USING SAP-FLOW TECHNOLOGY FOR SCHEDULING IRRIGATION
Article number
694_27
Pages
165 – 171
Language
English
Abstract
Mismatch between water applied during irrigation and that required by the crop for transpiration is a major cause of poor returns per unit water use and of land degradation.
Advances in commercial sap-flow gauges should provide opportunities for improving water management in tree-horticulture, but this has not been widely explored.
In this study we tested the capability of sap-flow gauges to detect water-stress and, hence a need for irrigation, by withholding water for two months from actively growing, mature, grapevines.
Withholding irrigation reduced soil-water content in the 1.8 m soil-profile by almost 40% compared to where irrigation was maintained, but the reduced soil-water resulted in only a small decrease in the transpiration deduced from sap-flow throughout the 2-month period.
This was despite a 3-fold increase in stomatal resistance and a rise of 1.0 °C in leaf temperature for the stressed compared to the continuously irrigated vines.
Reasons for this response are not clear, but it is possible that the stressed-vines accessed water either directly from the watertable or from its capillary fringe.
Withdrawal of irrigation also did not result in yield decline for the stressed-vines.
The results showed the limitation of employing sap-flow systems in managing irrigation.
Other implications of these findings are explored including proposals on using weighted crop factor to match irrigation with grapevine water-requirements.
Advances in commercial sap-flow gauges should provide opportunities for improving water management in tree-horticulture, but this has not been widely explored.
In this study we tested the capability of sap-flow gauges to detect water-stress and, hence a need for irrigation, by withholding water for two months from actively growing, mature, grapevines.
Withholding irrigation reduced soil-water content in the 1.8 m soil-profile by almost 40% compared to where irrigation was maintained, but the reduced soil-water resulted in only a small decrease in the transpiration deduced from sap-flow throughout the 2-month period.
This was despite a 3-fold increase in stomatal resistance and a rise of 1.0 °C in leaf temperature for the stressed compared to the continuously irrigated vines.
Reasons for this response are not clear, but it is possible that the stressed-vines accessed water either directly from the watertable or from its capillary fringe.
Withdrawal of irrigation also did not result in yield decline for the stressed-vines.
The results showed the limitation of employing sap-flow systems in managing irrigation.
Other implications of these findings are explored including proposals on using weighted crop factor to match irrigation with grapevine water-requirements.
Publication
Authors
I.A.M. Yunusa, P. Lu, D. Eamus, R.R. Walker
Keywords
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