Managing water stress in olive (Olea europaea L.) orchards us-ing reference equations for midday stem water potential

Abstract

The irrigation surface of olive orchards has increased over recent decades. In zones affected, def-icit irrigation scheduling is a must. The aim of this work was to study water stress management based on reference equations for midday stem water potential. An experiment was conducted over three seasons in Seville (Spain) from 2020 to 2022. A young hedgerow olive orchard (cv Manzanilla de Sevilla) was irrigated using three different treatments: Control (full irrigated), RDI, and Rrainfed, in a completely randomized design (6 replications). Midday stem water po-tential and leaf conductance were measured throughout the three seasons. Stem water potential was more sensitive to water stress than leaf conductance and showed a clearer impact and rehy-dration. Individual data of stem water potential were grouped according to leaf conductance re-duction. The relationship of these stem water potentials and temperature or vapor pressure defi-cit was significant, linear and aligned to published baselines. Scattering in these equations in-creased when the leaf conductance reduction was greater. These reference equations would be useful to define moderate water stress conditions in the most sensitive processes, such as vegeta-tive or fruit growth. Definition of severe water stress conditions would be better established with constant values.