Greenhouse Soil Moisture Deficit under Saline Irrigation and Climate Change

The sustainability of protected horticultural crops in the Mediterranean region, typically under deficit irrigation and intensive cultivation practices, is facing increasing risks due to soil salinization. Climate change may augment this threat to ecosystem services. In this study, the SALTMED leaching requirements model was calibrated using soil moisture measurements from time domain reflectometry (TDR) sensors. Measurements are performed on a small-scale Solanum lycopersicum (tomato) greenhouse experiment that simulates semi-arid conditions in the RECARE Project Case Study in Greece (Timpaki basin in Crete). The use of local planting soil with initial Electrical Conductivity (ECe) 1.8 dS m-1 and local cultivation practices aim to replicate prevailing conditions at the Case Study. Plants are drip irrigated with two NaCl treatments: slightly (S) saline (ECw= 1.1 dS m-1) and moderately (M) saline water (ECw= 3.5 dS m-1), resulting to very high and excessively high ECe, respectively. Based on these approaches, the calibrated SALTMED model was used for simulating groundwater degradation by seawater intrusion. In order to estimate crop yield in a warmer future, climate model data obtained from 9 GCMs for the “worst case” Representative Concentration Pathway of 8.5 W m−2 of the 5th phase of the Coupled Model Intercomparison Project are corrected for bias against historical observations with the Multisegment Statistical Bias Correction method. Preliminary results predict that to sustain greenhouse productivity at current levels in the future, a substantial increase of water demand will be required.