This study investigates the possibilities of applying water generated from the atmosphere for agricultural processes, particularly hydroponic systems. A solar powered, off-grid greenhouse system is proposed as a theoretical solution to food production, in areas affected by water scarcity. Two experiments are conducted with the purpose of testing atmospheric water quality and how it performs in a hydroponic setting. The plausibility of powering said greenhouse system using solar energy is investigated, considering several available solar technologies. Ultimately, the footprint area required to install enough capacity to power the system is discussed, and the potential site of such a system is modelled and visualized. The experiments concluded that atmospheric water is likely suitable for hydroponic use. The study also found that the footprint area required for the greenhouse system probably can be considered reasonable for certain applications, but more research and advances within solar power technology would be beneficial | <p>2021-06-08</p>

Food security is a critical issue for the Arabian Peninsula countries due fast population growth, reduced domestic food production and the tighter global food markets because of trading partners�?? strained export surpluses. Water scarcity is a major concern for the AP. The renewable water resources per capita is considered the lowest in the world and has decreased from 1250 m3 in 1950 to 76.2 m3 in 2014. Furthermore, the projected water demand in AP for the year 2025 will exceed the double of the current groundwater availability, estimated at 8030M m3. In response to the alarming water situation, ICARDA in collaboration with the National Agricultural and Extension Systems (NARES) has established a program in AP, which has developed, evaluated, and introduced technology packages that empower growers to produce high-quality crops with less water. These technologies include: 1) the integrated forage production system based on indigenous plant species; 2) the introduction of spineless cactus as animal feed; and 3) protected agriculture with associated developed technologies such as soilless culture (hydroponics). Similarly, ICARDA and NARS works on date palm has resulted in improving water and land productivity for date production. Such water saving technology packages are being transferred to farmers in AP region through ICARDA and National scientists and extension agents. Conclusively, a noticeable impact on the on-farm water management through the increased productivity per unit of water and land created. The demand for more applied research in the region is inevitable to ensure an adequate level of food security based on Climate-smart agriculture practice | Azaiez Ouled Belgacem, Arash Nejatian, Mohamed Ben-Salah, Ahmed Moustafa. (31/8/2017). Water and Food Security in the Arabian Peninsula: Struggling for more actions. Journal of Experimental Biology and Agricultural Sciences, 5, pp. 550-561.

In view of a water-energy-food (WEF) nexus strategy, the present work assessed the bioenergy production potential of Halimione portulacoides used for the phytoremediation of nutrient-rich simulated wastewater from saltwater-based integrated multi-trophic aquaculture (IMTA). Specimens of this halophyte plant were grown in hydroponics under four different nutrient treatments with distinct nitrogen (N) and phosphorous (P) concentrations. Ultimate and proximate analysis, calorific value and thermogravimetric analysis coupled to mass spectrometry were used to assess the bioenergy potential of the non-edible biomass of the plants, namely the canes (C) and roots (R), and of commercial pellets (CP), which were used as benchmark. R and, especially, CP had higher carbon but lower oxygen content and larger volatiles but lower ashes than C. The higher heating values (HHV) of C (16–17 MJ kg⁻¹) and R (17–18 MJ kg⁻¹) were the same order as those of conventional energy crops and CP (20 MJ kg⁻¹). Although mass loss and associated gaseous emissions during temperature programmed pyrolysis occurred mainly between 250 and 650 °C for all biomasses, they took place at slightly higher temperatures for C > CP > R. In any case, the integrated gaseous emissions during the pyrolysis of C, R, and CP were very similar and included H₂, CH₄, CO, and CO₂ (syngas main constituents). Biomass production of C was affected by the nutrients load of the applied treatments, but this was not the case for R. Also, the nutrients treatments had no detectable effects on the biomasses’ ultimate or proximate analysis, HHV, thermal decomposition or resultant gaseous emissions. Thermal properties and behaviour of C and R were very similar to those of CP, showing their potential for bioenergy production and revealing that a WEF nexus strategy can be implemented in IMTA by energetic valorization of non-edible biomass of H. portulacoides used for water phytoremediation.

An indoor aquaponic system (i.e., the integration of fish culture with hydroponic plant production in a recirculating setup) was operated for maximizing water reuse and year-round intensive food production (Nile tilapia, Oreochromis niloticus, and leaf lettuce) at different fish feed to plants ratios. The system consisted of a fish culture component, solid removal component, and hydroponic component comprising six long channels with floating styrofoam rafts for holding plants. Fish culture effluents flowed by gravity from the fish culture component to the solid removal component and then to the hydroponic component. Effluents were collected in a sump from which a 1-horsepower in-line pump recirculated the water back to the fish culture tanks at a rate of about 250 L/min. The hydroponic component performed as biofilter and effectively managed the water quality. Fish production was staggered to harvest one of the four fish tanks at regular intervals when fish attained a minimum weight of 250 g. Out of the total eight harvests in 13 mo, net fish production per harvest averaged 33.5 kg/m³ of water with an overall water consumption of 320 L/kg of fish produced along with the production of leaf lettuce at 42 heads/m² of hydroponic surface area. Only 1.4% of the total system water was added daily to compensate the evaporation and transpiration losses. A ratio of 56 g fish feed/m² of hydroponic surface effectively controlled nutrient buildup in the effluents. However, plant density could be decreased from 42 to 25-30 plants/m² to produce a better quality lettuce.