The use of innovative technologies to improve treated wastewater irrigation of olive trees in the Souss-Massa region, Morocco

Treated wastewater (TWW) use represents a strategic prospect for sustainable agricultural development in water-scarce countries. The objective of this study was to evaluate the feasibility of adopting an innovative nozzle and irrigation management support (SIM) to promote the cultivation of olive trees under TWW in Morocco. The study involved 4-year-old olive trees irrigated according to the water requirement estimated by both the SIM model and the FAO56 method. The results showed that neither agronomic and physiological parameters nor leaves were affected by irrigation with TWW. However, the soil reacted differently as its alkalinity but witnessed a decrease in the fresh water (FW) treatments. The soil solution electrical conductivity was generally higher for TWW than FW. The savings on water and fertilizer costs generated by the TWW and TWW + SIM treatments are 570€ and 585€/ha, respectively, and the adoption of the two innovations generates additional net benefits equal to 45,000€, while to the nozzle with TWW alone, additional net benefits were observed that is 42,000€. A minimum increase in return of only 0.6% is needed to cover investment costs over the 30-year life of the project and the investment could be profitable even with a decrease in return of 48%.