Validation of an online system for the continuous monitoring of tree water status for sustainable irrigation managements in olive (Olea europaea L.)

Abstract

As a result of climate change a large reduction of agricultural water through improved irrigation management is a major need for agriculture sustainability. To this aim, always more sensitive sensors to monitor plant water status have been developed in recent years. Among them, the leaf patch clamp pressure probes are very promising for water management of olive but until now have been tested only in few environmental and management conditions. In this work these sensors have been tested for two consecutive years on two completely different management systems: a traditional rainfed orchard and a super high density (SHD) drip irrigated orchard. Within the SHD orchard the probes have been installed on two different genotypes characterize by different vigor and productive potential. Stem water potential and gases exchange have been measured at regular intervals and used as reference to detect water status of the trees. The high correlation observed between the leaf patch clamp pressure probes and Ψswp, independently from the year and the treatment, confirmed the high potential of the continuous system. The inversion of the daily curve of the leaf patch clamp pressure probes reading was observed when Ψswp decreased under the value of −2.2/−2.5 MPa suggesting the possibility to use this indicator to detect high water stress levels. Anyway, considering that at this level of stress the plants had already strongly reduced the gas exchanges by 40–50% with respect to their values at Ψswp above −2 MPa, with consequence on carbohydrate production that can affect productivity, rise the need to find other indicators that enable to differentiate water status at lower stress levels. From the result of this work a promising indicator seems the relative increase of the daily minimum value of the leaf patch clamp pressure probe readings, as suggested by its correlation with Ψswp.