Onan Agaba

Date palms are high-value fruit trees widely cultivated in arid regions due to their resilience to harsh climates and saline soils. In Israel’s hyper-arid Arava Valley, date palm cultivation depends on high-frequency irrigation using saline groundwater (~3 dS/m). Large irrigation volumes are needed to meet water demands and leach salts below the root zone, but this has caused environmental issues. Farmers report poor drainage which causes puddles that attract mosquitoes and hinder agricultural machinery. To improve infiltration and salt leaching, farmers have started building soil mounds around date palms. This study aimed to optimize mound geometry and soil hydraulic parameters by combining field data with a calibrated HYDRUS model. Soil mounds (60 cm height, 200 cm perimeters) were constructed using different sand-to-compost ratios: 100-0, 75-25, 55-45, 25-75, and 0-100. Sensors (TDR, tensiometers, suction cups) monitored soil conditions at various depths. HYDRUS model sensitivity analysis identified key parameters affecting infiltration and leaching. Results showed that compost-based mounds retained higher moisture, while the 55-45 mound exhibited ponding. Compost-dominant mounds (0-100, 25-75) maintained stable EC (~5 dS/m), whereas sand-dominant mounds (100-0, 75-25) showed EC fluctuations (2.5–3.5 dS/m) which indicated variable salt concentrations. The HYDRUS model accurately predicted soil moisture across treatments (RMSE: 0.0112–0.0164 cm³/cm³). Saturated hydraulic conductivity (Ks) was the most influential parameter. Optimization showed that 100-0 and 75-25 mounds maximized infiltration and moisture retention. Thus, using a calibrated HYDRUS model to design soil mounds with optimal dimensions and parameters improves infiltration, salt leaching, and irrigation efficiency in date palm cultivation.