ISHS Acta Horticulturae 689: VII International Symposium on Grapevine Physiology and Biotechnology
MODELLING THE EFFECT OF CLIMATE CHANGE ON GRAPEVINE WATER RELATIONS |
| Authors: | H.R. Schultz, E. Lebon |
| Abstract:
According to the Intergovernmental panel on climate change (IPCC 2001), global warming will increase air temperature in Western and Northern Europe between 2.5 and 4.5 °C by the end of this century. Most climate models predict an increase in precipitation rates during winter as a result of the temperature-driven increase in the velocity of the hydrological cycle over Europe. Results are less clear for the vegetation period but dryer conditions are more likely. Higher temperatures will cause higher rates of evaporation, both from soil and from plants. Since grapevines are mostly not irrigated in Europe, there may be a substantial risk in terms of more frequent and more severe droughts with possible adverse effects on yield and quality. To assess these possible effects, we developed a model capable of simulating vine responses to drought. For this a geometrical canopy model describing radiation absorption and partitioning between grapevines and soil was coupled to a soil water balance routine describing a bilinear change in relative transpiration rate as a function of the fraction of soil transpirable water (FTSW). The model can account for changes in soil evaporation after precipitation events and has previously been validated. We used a data set from a vineyard site and simulated different climatic scenarios. Through a relationship between FTSW and pre-dawn water potential (  PD), which has proven to be stable over large differences in soil water storage capacity from different vineyard sites, we were able to simulate climate change effects on ΨPD and consequently its effects on photosynthesis and stomatal conductance.
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