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Water management policies in desert agricultural regions critically influence both crop choices and ecosystem dynamics, yet their cascading ecological impacts remain poorly understood. In particular, the complex interactions between water quality, agricultural practices, and wildlife responses require further investigation to inform sustainable management in desert landscapes. Here, we evaluate how water policy, particularly seawater desalination initiatives influencing irrigation and cropping practices, shapes ecological systems in a hyperarid region, the southern Arava Valley of Israel. We integrated community-level questionnaires, agricultural records, animal field observations, and spatially explicit scenario tools into a mixed-methods framework to model social–ecological cascades linking water policy to predator dynamics. Bayesian Belief Networks combined with Generalized Linear Models of predator abundance were used to assess how improved water quality affects cropping patterns and, in turn, regional predator populations. Our findings indicate that desalination is unlikely to alter the predominance of date orchards or the high abundance of range-expanding jackals associated with these systems. However, water quality-driven expansion of field crops corresponds to lower modelled fox abundance and shifts in predicted predator interactions, while jackal populations remain largely influenced by date orchard availability. Under business-as-usual scenarios with lower water quality, farmers are likely to reduce field crop areas, corresponding to further changes in regional predator abundance. These findings suggest that water policy decisions may generate cascading social–ecological responses on both agricultural practices and local desert ecosystems, emphasizing the need for strategies that balance agricultural productivity with ecological sustainability in arid landscapes.

Irrigation of crops in arid regions with marginal water is expanding. Due to economic and environmental issues arising from use of low-quality water, irrigation should follow the actual crop water demands. However, direct measurements of transpiration are scant, and indirect methods are commonly applied; e.g., the Penman–Monteith (PM) equation that integrates physiological and meteorological parameters. In this study, the effects of environmental conditions on canopy resistance and water loss were experimentally characterized, and a model to calculate palm tree evapotranspiration ETcwas developed. A novel addition was to integrate water salinity into the model, thus accounting for irrigation water quality as an additional factor. Palm tree ETcwas affected by irrigation water salinity, and maximum values were reduced by 25 % in plants irrigated with 4 dS m⁻¹and by 50 % in the trees irrigated with 8 dS m⁻¹. Results relating the responses of stomata to the environment exhibited an exponential relation between increased light intensities and stomatal conductance, a surprising positive response of stomata to high vapor pressure deficits and a decrease in conductance as water salinity increased. These findings were integrated into a modified ‘Jarvis–PM’ canopy conductance model using only meteorological and water quality inputs. The new approach produced weekly irrigation recommendations based on field water salinity (2.8 dS m⁻¹) and climatic forecasts that led to a 20 % decrease in irrigation water use when compared with current irrigation recommendations.

There are gaps in our knowledge of the effects of irrigation water quality and amount on yield and postharvest quality of pepper fruit (Capsicum annuum L.). We studied the effects of water quality and quantity treatments on pepper fruits during subsequent simulated storage and shelf-life. Total yield decreased with increasing water salinity, but export-quality yield was not significantly different in fruits irrigated with water of either 1.6 or 2.8 dS/m, but there was a 30–35% reduction in export-quality yield following use of water at 4.5 dS/m. Water quantity hardly affected either total or export-quality yield. Water quality but not quantity significantly affected fruit weight loss after 14 days at 7 °C plus three days at 20 °C; irrigation with water at 2.8 dS/m gave the least weight loss. Fruits were significantly firmer after irrigation with good-quality water than with salty water. The saltier the water, the higher was the sugar content. Vitamin C content was not affected by water quality or quantity, but water quality significantly affected antioxidant (AOX) content. The highest AOX activity was found with commercial quality water, the lowest with salty water. Pepper yield benefited by irrigation with fresh water (1.6 dS/m) and was not affected by water quantity, but post-storage fruit quality was maintained better after use of moderately-saline water (2.8 dS/m). Thus, irrigation water with salinity not exceeding 2.8 dS/m will not impair postharvest quality, although the yield will be reduced at this salinity level.

Yield and transpiration of juvenile date palms (Phoenix dactylifera L., cv. Medjool) were studied under conditions of increasing salinity and boron in lysimeters. Twenty seedlings were planted and grown in 20 lysimeters and irrigated with combinations of four salinity and five B irrigation concentrations. A linear decrease was found for both yield and for transpiration in response to increased soil saturated paste salinity for the treatments having lower B concentrations (0.0278, 0.185 and 0.4625 mmol l-1). Yield and transpiration also decreased with increased B concentration. While increases in soil saturated paste B from 0.3 to 1.5 mmol l-1 caused substantial declines in yield and transpiration, subsequent increased B to 3 mmol l-1 caused only minor reductions. Response to salinity and to excess B was witnessed from the lowest tested levels when each of the variables was isolated. Growth response to combined conditions of salinity and B behaved according to the dominant of the two stress causing factors and did not show additive effects. Dynamics of plant water uptake and tree growth observed for salinity and boron occurring independently and together were summarized by decreased water uptake but not ion accumulation for NaCl and CaCl salts and by boron that was accumulated in leaves and subsequently was associated with reduced tree size. It is suggested that while mechanisms for plant response to salinity are dominated by lowered soil water potential (osmotic stress), boron becomes toxic as it accumulates to a threshold level in plant tissue.