A comparative study of traditional vs. plant-sensor based irrigation across multiple sites: consequences on water savings and vineyard economics–application during a drought in California

Abstract

By monitoring plant water use continuously, new irrigation techniques can be implemented to promote more efficient vineyard water use. In order to demonstrate the impact of a new plant-based irrigation method in terms of water savings and vineyard performances, we designed an experiment across multiple vineyards in contrasted climatic condition during a very dry season. We selected and split 6 uniform vineyard areas to compare the effect of 2 irrigation strategies over 3 distinct wine growing regions. First we implemented a sap flow sensor-monitoring method to track continuous vine water deficit variations. Second we triggered irrigation according to real time assessment of vine water deficit based on sap flow and climatic data. Third, we evaluated the effect of sap flow-based irrigation based on real time monitoring of plant water deficit on vineyard performances and water savings by comparing two irrigation strategies. Under traditional strategy, water is applied based on empirical knowledge, visual observations and some measurements but without any specific rules. Under experimental strategy, irrigations are triggered each time vine water deficit reaches a threshold value. Our study demonstrates that more conservative irrigation practices can be adopted with the experimental strategy. Despite reducing irrigation volume in a context of drought (40% to 100% less water volume is used in the experimental treatment), no yield losses were reported and sugar accumulation was observed at a similar rate. By focusing on a few reference sites and by integrating various sources of vineyard data into a framework, it is possible to track vine water deficit in real time and to extrapolate irrigation decisions over large areas. Implications to implement more conservative and varietal-specific irrigation strategies are discussed.