Stem water potential estimation of drip-irrigated early-maturing peach trees under Mediterranean conditions

Abstract

In the last decade deficit irrigation strategies allowed growers to deal with water shortages, while monitoring stem water potential (Ψstem) is deemed essential for maximising fruit yield and quality. However, because of the intensive labour involved in measuring Ψstem, alternative methods are desirable. The experiment described was conducted in Murcia (Spain) with adult peach trees (Prunus persica (L.) Batsch cv. Flordastar) submitted to different drip irrigation treatments, measuring Ψstem with a pressure chamber and the soil water content with a neutron probe. Agro-meteorological variables were recorded. Seasonal patterns of stem water potential provide a useful diagnostic tool for irrigation management in peach trees. Rainfall events and the meteorological conditions prevailing in autumn pointed to the resilient nature of the peach cultivar studied. Fitting Ψstem by linear regression analysis as a function of soil and atmosphere yielded a significant correlation, with the soil water content being the main contributor to estimating Ψstem. Linear regression analysis highlighted the importance of considering plant water status as a function of the peach tree cultivar, the atmospheric conditions in which it develops and the soil water conditions resulting from irrigation. A multiple linear regression equation based on soil water content in the soil profile, mean daily air vapour pressure deficit (VPDm) and growing degree hours (GDH) data explained 72% of the variance in Ψstem, and is proposed as an alternative to the field measurement of Ψstem.