Monitoring water relations in hazelnut plantations located in Cancon (France) - Results 2016-2017 - Final Report

The productivity of an orchard is strictly dependent on water availability. This is particularly true for hazelnut, which behaves as a “water-saver” species: it strongly reduces stomatal conductance (and thus photosynthesis and growth) when soil water deficit occurs. It is also well known that nut yield is strictly influenced by plant growth (Baldwin 2010). To optimize irrigation and nut yield it is thus essential to predict the transpiration in relation to meteorological conditions and different irrigation. Compared to most other common orchards the irrigation management in hazelnut can be greatly improved. In most cases irrigation scheduling is based on the use of general physical models (Penman-Monteith method) corrected for the specific orchard. However in this case is not easy to incorporate some physiological responses such as, for example, the stomatal closure with increasing VPD (vapor pressure deficit) or variation in structural parameters of the plantation, such as changes in total leaf area with age. To the specific site in France we tried also to link the water related dynamic to the carbon assimilation in order to provide indications for improving the water use efficiency of the plantation.