Water stress thresholds for regulated deficit irrigation in pistachio trees: Rootstock influence and effects on yield quality

摘要

The response of "Kerman" pistachio trees budded on three different rootstocks (Pistacia terebinthus, Pistacia atlantica and Pistacia integerrima) to regulated deficit irrigation(RDI) in shallow soils was studied for 3 years. The trees were either fully irrigated (C treatment) or subjected to deficit irrigation during Stage II of fruit growth with two water stress thresholds (T1 and T2). The irrigation scheduling for fully-irrigated trees and water-stressed trees was managed by means of midday stem water potential (Psi(stem)) measurements. The use of direct measurements of the water status allowed estimating accurately the irrigation requirements for pistachio trees, with water reductions ranging from 46 to 205 mm in fully-irrigated trees. The combination of the Psi(stem) use and the RDI regime saved 43-70% in T1 and 48-73% in T2 of water compared to the calculated crop evapotranspiration (ETc) for fully irrigated treatment (C).