Scheduling a deficit irrigation strategy from leaf turgor measurements: impact on water status, gas exchange and oil yield

Regulated deficit irrigation (RDI) is among the most promising irrigation strategies for super-high-density (SHD) olive orchards, and plant-based sensors to monitor water stress are useful tools to manage RDI. In this study, we evaluated the suitability of leaf turgor-related measurements, made with ZIM probes, to schedule an RDI strategy aimed to supply 45% of the irrigation needs to an 'Arbequina' olive orchard with 1667 trees ha(-1) (45RDI(TP) treatment). For comparison, we used a similar treatment but in which irrigation was scheduled with the crop coefficient approach (45RDI(CC)). In addition, we had a full irrigation (FI) treatment aimed to replace 100% of the irrigation needs (IN). We assessed the effect of both 45RDI(TP) and 45RDI(CC) on water status, stomatal conductance and net photosynthesis, as well as on water productivity for oil yield. There were no differences between 45RDI(CC) and 45RDI(TP) in any of the evaluated variables. We concluded that our irrigation approach based on the use of ZIM probes is useful to schedule RDI in SHD olive orchards, and that it is a suitable alternative to the crop coefficient approach, at least in those orchards for which crop coefficient values are unknown.