Soil and plant water indicators for deficit irrigation management of field-grown sweet cherry trees

© 2018 Elsevier B.V. A two-year experiment with sweet cherry (P. avium L. cv Prime Giant) trees was carried out to ascertain which of the following commonly used soil and plant water indicators is most effective for deficit irrigation scheduling: ¿ stem (midday stem water potential), MDS (maximum daily branch shrinkage), g s (stomatal conductance), ¿ v (soil volumetric water content), ¿ m (soil matric potential). For this, soil and plant water relations, as well as the physiological and agricultural responses of trees to three different irrigation treatments, were evaluated. The irrigation treatments imposed were: i) a control treatment (CTL) irrigated at 110% of crop evapotranspiration (ET c ) throughout the growing season, ii) a regulated deficit irrigation treatment (RDI), which met 100% ET c at preharvest and during floral differentiation and 55% ET c during the postharvest period and iii) a treatment based on normal farming practices (FRM). MDS was the first indicator to detect water stress, while ¿ m showed the highest sensitivity postharvest, when it was closely related with ¿ stem . Consequently, a multiple linear regression equation based on average ¿ m at a depth of 25 and 50 cm, and mean daily air vapor pressure deficit (VPD) was established to estimate ¿ stem . The estimated ¿ stem explained 84% of the variance in the measured ¿ stem . Hence, the equation proposed can be used as a tool to estimate ¿ stem and for irrigation scheduling. Based on the relation MDS vs. ¿ stem and the observed agronomic response, a postharvest threshold value of ¿1.3 MPa is proposed for deficit irrigation management in `Prime Giant¿ cherry trees.