Articles
RELATIONSHIPS BETWEEN RELATIVE TRANSPIRATION OF GRAPEVINES AND PLANT AND SOIL WATER STATUS IN PORTUGAL’S DOURO WINE REGION
Article number
922_34
Pages
261 – 267
Language
English
Abstract
In NE Portugal, winegrapes are a major crop being an important source of income for local farmers.
Located in deep valleys, protected by mountains, the climate in the Demarcated Region of Douro is characterised by scarce rainfall and large evapotranspiration losses during the summer season.
A study was undertaken to evaluate the effect of different water availability on soil and plant water status.
One thermal dissipation technique (Granier method) was used to continuously monitor sap flow of trickle irrigated and traditional rain-fed grapevines for two years (2008-09), in a commercial mature vineyard planted with the wine grape cultivar Moscatel Galego-Branco (syn. Muscat à Petits Grains). Relative transpiration (RT) was calculated as the ratio between sap flow of stressed rain-fed plants and well-watered ones.
Predawn leaf water potential (Ψp) and soil water content (SWC) within a 1.5 m soil profile were also measured as stress indicators for irrigation management.
Additionally, leaf area, yield and must quality were assessed.
RT values ranged from 1.0 in early summer (before irrigation supply) to about 0.5 (2008) or 0.4 (2009) towards harvest in agreement with increasing soil water depletion and decreasing Ψp values.
RT showed a closer relationship with Ψp as compared with SWC, suggesting that Ψp is a better indicator of water availability that can be used when irrigation is implemented in the region.
Located in deep valleys, protected by mountains, the climate in the Demarcated Region of Douro is characterised by scarce rainfall and large evapotranspiration losses during the summer season.
A study was undertaken to evaluate the effect of different water availability on soil and plant water status.
One thermal dissipation technique (Granier method) was used to continuously monitor sap flow of trickle irrigated and traditional rain-fed grapevines for two years (2008-09), in a commercial mature vineyard planted with the wine grape cultivar Moscatel Galego-Branco (syn. Muscat à Petits Grains). Relative transpiration (RT) was calculated as the ratio between sap flow of stressed rain-fed plants and well-watered ones.
Predawn leaf water potential (Ψp) and soil water content (SWC) within a 1.5 m soil profile were also measured as stress indicators for irrigation management.
Additionally, leaf area, yield and must quality were assessed.
RT values ranged from 1.0 in early summer (before irrigation supply) to about 0.5 (2008) or 0.4 (2009) towards harvest in agreement with increasing soil water depletion and decreasing Ψp values.
RT showed a closer relationship with Ψp as compared with SWC, suggesting that Ψp is a better indicator of water availability that can be used when irrigation is implemented in the region.
Authors
A.C. Malheiro, I.N. Gonçalves, A.A. Fernandes-Silva, J.C. Silvestre, N.S. Conceição, T.A. Paço, M.I. Ferreira
Keywords
sap flow, water stress, predawn leaf water potential, Vitis vinifera L.
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