Can within-season grapevine predawn leaf water potentials be predicted from meteorological data in non-irrigated Mediterranean vineyards?

Abstract

Aims: Climate-based indices exist for viticulture, particularly for modelling phenological events, but not for vine water status. In this work, climatic variables are linked to the temporal evolution of the water status of the vine

Methods and Results: Within-season time-series of predawn leaf water potential from previous studies across 8 seasons in the south of France were collated. Meteorological data were also collected at each site. A stepwise linear regression model was developed to predict the mean predawn leaf water potential of a vineyard block at a given date from climatic variables and time. Variables selected were growing degree days, short-term humidity and temperature effects. Application of the stepwise model to an independent data set, collected at the other two research sites, produced a linear response but required a local calibration at each site.

Conclusion: The analysis demonstrated that climatic variables can be used for predicting the temporal evolution of vine water stress in non-irrigated vineyards.

Significance and impact of study: The modelling can assist with within-season crop management and future vineyard planning/development in non-irrigated regions. In irrigated vineyards the application is more restricted but it may be used to identify when to start irrigation.