A generic method to analyze vine water deficit continuously

In the context of global warming, water scarcity is becoming an increasing issue worldwide. However, the reference method to characterize vine water deficit is based on water potential measurement, which is a destructive and discontinuous method. The current climatic context emphasizes the need for more precise and more continuous vineyard water use measurements in order to optimize irrigation and vine water deficit monitoring.

Our work proposes a quantitative method to characterize vine water deficit variations in a continuous fashion. Combining sap flow and climatic raw data, the framework uses expert knowledge and mathematical modeling to characterize dry soil crop coefficient (KcB) and automatically compute a daily water deficit index Ks. As a case study we used an experimental design set in French vineyards where contrasted vine water deficit profiles were obtained by using differential irrigation treatments.

We analyzed Tr/ETref ratio variations to identify the timing and value of maximal KcB. After that preliminary step, we computed and aggregated Ks profiles for each treatment and compared irrigation effects on Ks profiles. Because sap flow and climatic sensors are installed outdoor, determination of maximal KcB value is particularly sensitive to environmental variations. As such, we studied the effect of measurement uncertainties on KcB computation and Ks profile by imposing variations in the timing and value of KcB. Implications and perspectives to improve irrigation practices are discussed.