Integrating Field Data and Modeling for Sustainable Wastewater Irrigation Management: Case Studies from Jordan and Palestine

Water shortages, overexploitation and sectoral conflicts have prompted the use of treated wastewater (TWW) in agriculture. While TWW provides essential nutrients, improper management can harm soil and crops. To address this, case studies from Jordan and Palestine—where alfalfa and citrus crops are exclusively irrigated with TWW—were conducted to identify suitable irrigation schedules and assess adverse impacts on crops and soils. The Safe Irrigation Management (SIM) model was used to simulate irrigation in 2021, considering TWW quality, quantity, and initial soil conditions. Two scenarios were examined: FARMOD, based on farmers’ planning, and ON-DEMAND, suggested by SIM. The results showed significant differences in irrigation frequencies and volumes between the two scenarios. The ON-DEMAND scenario demonstrated improved nitrogen and phosphorus uptake, lower soil electrical conductivity (ECe 1.5 dS·m⁻¹), and reduced E. coli levels (4 log₁₀ CFU·g⁻¹). A hypothetical scenario assuming initial soil conditions prior to TWW use yielded even lower ECe (0.8 dS·m⁻¹) and E. coli (3.3 log₁₀ CFU·g⁻¹). Sensitivity analysis identified ECe and nitrogen crucial water quality indicators requiring continuous monitoring. Integrating field data and modeling practices is vital to maintaining soil quality, supporting long-term TWW reuse especially where it is a widely adopted irrigation solution.