In most desert ecosystems of the Arabian Peninsula Region (APRP), vegetable production is carried out under controlled environment structures covered with polycarbonate sheets and inbuilt evaporative cooling systems. The areas with mild winter, polycarbonate cover and evaporative cooling are not required. The former can be replaced by insect proof net and the latter with a root zone cooling system to maintain the root zone area temperature at 25 ℃ at early summer. The aim of the study was to test a combination of five technologies, namely insect proof net, hydroponic closed system, root zone cooling (RZC) through fertigation chilling, ultra-low-pressure drippers, and low establishment cost of solar energy and test the potential of the system to extend the production period into the summer. The trials have been carried out in the Sultanate of Oman and UAE simultaneously on Cucumber. The results showed that by replacing the polycarbonate cover with an insect prove net and the evaporative cooling with solar energy powered ultra-low-pressure drippers, the water and energy consumption has been reduced by 85% and 90%, respectively, production period was extended to early August. Despite the implementation of these advanced techniques aimed at reducing production costs, the yield and profitability of cucumber cultivation remained limited specialty in UAE. However, the research showcased the promising potential of RZC powered by solar energy in extending the production period of net houses throughout the hot summer months.

This study assessed six tomato (Solanum lycopersicum L.) cultivars within an integrated solar-powered closed hydroponic system in Al Dhaid, UAE (25°16′11.2″ N, 55°55′52.2″ E). The system combined an insect-proof net house, closed hydroponics, root-zone cooling, ultra-low-energy drip irrigation, and a cost-effective solar-powered reverse osmosis (RO) desalination unit to address salinity constraints. The cultivars, selected for their adaptability to controlled environments in the UAE, were evaluated for yield, water-use efficiency (WUE), and fertilizer-use efficiency (FUE). Among them, Torcida recorded the highest mean yield (0.619 kg/m²/harvest), WUE (27.1 kg/m³), FUE (26.5 kg fruit/kg fertilizer), and marketable fruit ratio (66.3%), followed by Roenza, Eviva, and SV 4129 TH; Lamina was intermediate, while Saley, a bushy type, produced the lowest yield. The top cultivars achieved cumulative yields exceeding 7 kg/m²—surpassing regional open-field benchmarks (4–5 kg/m²; 3–6 kg/m³). Compared with conventional cooled hydroponic greenhouses (3.5 kg/plant; 8 kg/m³), the system demonstrated similar productivity using three times less water. The RO unit produced water at baseline 1.05 USD/m³—58–68% below regional tariffs—while minimizing reliance on grid electricity and mechanical cooling. Overall, the integrated solar-powered hydroponic–RO model proved technically reliable, resource-efficient, and economically viable, offering a scalable solution for sustainable vegetable production in hyper-arid regions.

This study assessed six tomato (Solanum lycopersicum L.) cultivars within an integrated solar-powered closed hydroponic system in Al Dhaid, UAE (25°16′11.2″N, 55°55′52.2″E). The system combined an insect-proof net house, closed hydroponics, root-zone cooling, ultra-low-energy drip irrigation, and a cost-effective solar-powered reverse osmosis (RO) desalination unit to address salinity constraints. The cultivars, selected for their adaptability to controlled environments in the UAE, were evaluated for yield, water-use efficiency (WUE), and fertilizer-use efficiency (FUE). Among them, Torcida recorded the highest mean yield (0.619 kg m⁻² harvest⁻¹), WUE (27.1 kg m⁻³), FUE (26.5 kg fruit kg⁻¹ fertilizer), and marketable fruit ratio (66.3%), followed by Roenza, Eviva, and SV 4129 TH; Lamina was intermediate, while Saley, a bushy type, produced the lowest yield. The top cultivars achieved cumulative yields exceeding 7 kg m⁻²—surpassing regional open-field benchmarks (4–5 kg m⁻²; 3–6 kg m⁻³). Compared with conventional cooled hydroponic greenhouses (3.5 kg plant⁻¹; 8 kg m⁻³), the system demonstrated similar productivity using three times less water. The RO unit produced water at 1.05 US$ m⁻³—58–68% below regional tariffs—while minimizing reliance on grid electricity and mechanical cooling. Overall, the integrated solar-powered hydroponic–RO model proved technically reliable, resource-efficient, and economically viable, offering a scalable solution for sustainable veg-etable production in hyper-arid regions.

Saline groundwater and high evaporative demand constrain forage production in hyper-arid drylands, yet suitable water-management strategies remain poorly defined. We combined two years of multi-cut barley field experiments in Abu Dhabi, United Arab Emirates, with APSIM Next Generation simulations to assess production limits and water-salinity management. Three irrigation-water salinities (2000, 6000 and 10000 ppm total dissolved solids) and irrigation levels (50, 75 and 100% crop evapotranspiration, ETc) were tested on ten genotypes in 2024–25 and five in 2025–26. Seasonal dry biomass at 2000 ppm reached 9.73 and 7.91 t ha⁻¹; losses were 8 and 29% at 6000 ppm and 25 and 45% at 10000 ppm, with no significant genotype × salinity interaction. Irrigation at 50% ETc nearly doubled irrigation-water productivity (14.5 versus 7.8 kg ha⁻¹ mm⁻¹). APSIM reproduced biomass and regrowth well (calibration R² = 0.90, RMSE = 85 g m⁻²; evaluation R² = 0.61, RMSE = 172 g m⁻²). Simulations across 181 farms estimated potential yield near 14 t ha⁻¹ season⁻¹. Attainable yield remained close to potential below about 20 dS m⁻¹ root-zone salinity but declined rapidly above this level. Water productivity was highest at 60–80% reference evapotranspiration, about 25% higher than full irrigation. Combining deficit irrigation, nitrogen management, sowing date and genotype increased yield from 1.9 to 13.9 t ha⁻¹ using 20% less irrigation water and reduced between-season variability from 98 to 6%. Forage barley can therefore be produced with saline groundwater when root-zone salinity is controlled and irrigation, leaching and nitrogen are managed together.