This study was conducted to evaluate the effects of varying irrigation salinity levels on the physiological and biochemical responses of Chilean white quinoa (Chenopodium quinoa Willd.) in two greenhouse cultivation seasons (2015 and 2016) in Cherfech, Tunisia. The experiment involved three treatments: T0 (control, using tap water with EC = 1.4 dS/m), T1 (EC = 9.0 dS/m), and T2 (EC = 18 dS/m). The results showed significant differences with multiple parameters. Quinoa irrigated with T2 exhibited superior growth and seed yield compared to the other treatments in both seasons. Additionally, soluble protein content increased significantly in the second season, especially in T2, while nitrogen content also rose notably from T0 to T2 in 2016. Bioactive compounds, such as vitamin C, phenols, flavonoids, DPPH, and ABTS, were highest in T2. Mineral content (K, P, Na, Mg, Zn, Ca, and Fe) showed considerable variation, with T2 generally presenting the highest levels. Amino acids exhibited notable changes, with an increase from T1 to T2, though lysine content decreased under T2 conditions. These findings indicate that quinoa can effectively adapt to saline irrigation, positioning it as a promising crop for cultivation in saline-affected regions.

The concept of the water footprint (WF) has not adequately explored the combined effects of climate change and salinity. For this aim, the effects of future climate conditions on tomato WF irrigated with moderately saline water (EC = 2.9 dS m⁻¹) were examined, considering an expected increase in salinity reaching 5.9 dS m⁻¹ by 2050. Reference evapotranspiration (ETo), effective rainfall (ER), tomato crop evapotranspiration (ETc), leaching requirement (LR), net irrigation requirement (NIR), and tomato yield were estimated using CropWat and AquaCrop models. The blue (WFBlue), green (WFGreen), gray (WFGray), and total WF (TWF) were calculated. Results showed that ETo, ETc, and ER are expected to increase, while tomato yields will show a slight decrease. NIR is expected to increase depending on climate change scenarios and the increasing salinity of water irrigation. Calculated WF components showed significant increases, which consequently led to an increase in WFT exceeding the Tunisian national and regional levels by 15% and 18% between 2023 and 2050 under two scenarios, RCP4.5 and RCP8.5. The results highlighted the importance of WF for developing adaptation strategies to manage limited water resources, while advanced research on a large scale based on smart assessment tools is required to find best practices for water use reduction.