In arid countries like Oman, fan–pad cooling systems are commonly used in greenhouse cultivation. However, in such harsh environmental conditions, a fan–pad cooling system can be inefficient, result in high water and energy consumption, and may cause plant and soil pathogens issues. To address these challenges, this study evaluated the technical performance of a greenhouse designed with the new concept of an on-grid, solar-powered, and fan-chiller tube bank (FCTB) cooling system, focusing on water use efficiency (WUE) and energy use efficiency (EUE) following pot-grown okra. In addition, greenhouse gas (GHG) emissions and financial aspects were evaluated through cost–benefit and cash flow analyses. This research was conducted with a Quonset side-walled single-span greenhouse equipped with a solar-powered FCTB cooling system and automatic scheduled irrigation system. Water and electricity consumption was recorded, and surplus energy supplied to the electricity grid was estimated. The greenhouse efficiencies were evaluated by computing the EUE, total WUE, cooling water use efficiency (CWUE), and irrigation water use efficiency (IWUE). The solar-powered FCTB greenhouse enhanced EUE, achieving a value of 1.16 and a positive net energy of 163.87 MJ·m⁻². The WUE, CWUE, and IWUE were 0.91 kg·m⁻³, 1.63 kg·m⁻³, and 2.07 kg·m⁻³, respectively. The economic assessment showed that okra cultivation with a solar-powered FCTB cooling system was economically unfeasible, as indicated by a benefit–cost ratio of 0.88. However, cucumber (IRR 46%, NPV 2.13 × 10⁴ USD) and cherry tomatoes (IRR 38%, NPV 1.98 × 10⁴ USD) demonstrated economic feasibility as supported by positive net present value (NPV) and the internal rate of return (IRR) values. Furthermore, incorporating solar energy with the FCTB cooling system enhanced the greenhouse’s sustainability, efficiencies, and profitability. This study recommends further research with this system for Oman’s seasonal effect with high-value crops and optimizing the size of the solar panel system to see how the energy and other efficiency components will vary.

The effective management of produced water (PW), a by-product of oil extraction in Oman, is essential for sustainable water use and environmental protection. PW contains petroleum residues, heavy metals, and salts, which require treatment before safe reuse. In the Nimr oil field, PW undergoes partial treatment in constructed wetlands vegetated with buffelgrass (Cenchrus ciliaris). This study investigated the reuse potential of treated PW for irrigation through two parallel field experiments conducted at Sultan Qaboos University (SQU) and the Nimr wetlands site. At the SQU site, native halophytic plants were irrigated with three water sources: treated municipal wastewater, underground water (from an on-site well), and treated produced water. At the Nimr site, irrigation was conducted using underground water and treated PW. Two soil types were used: well-draining control soil and Nimr soil from southern Oman. The treatments included: (i) PW + control soil, (ii) PW + Nimr soil, (iii) PW + gypsum (3.5 g/kg soil), (iv) PW + biochar (10 g/kg soil), (v) underground water + control soil, and (vi) treated municipal wastewater + control soil. Biochar, produced from locally sourced buffelgrass via low-temperature pyrolysis (300 °C for 3 h), and gypsum (46.57% acid-extractable sulfate) were mixed into the soil before sowing. The impact of each treatment was assessed in terms of soil quality (salinity, boron, major cations), plant physiological responses, and mineral accumulation. PW irrigation (TDS ~ 6500–7000 mg/L) led to a sixfold increase in soil sodium and raised boron levels in plant tissues to over 200 mg/kg, exceeding livestock feed safety limits. Copper remained within acceptable thresholds (≤9.5 mg/kg). Biochar reduced boron uptake, but gypsum showed limited benefit. Neither amendment improved plant growth under PW irrigation. These findings highlight the need for regulated PW reuse, emphasizing the importance of soil management strategies and alternating water sources to mitigate salinity stress.

Mitigating Environmental Risks of Wastewater Reuse for Agriculture | InTechOpen, Published on: 2017-03-29. Authors: Ahmed Al‐Busaidi and Mushtaque Ahmed

(2011). A short communication on growing Jatropha in Oman. International Journal of Environmental Studies: Vol. 68, No. 1, pp. 25-29.