Reducing Irrigation Water Consumption Added for Onion by Using the Technique of Isolating Sandy Soil with Plastic Sheet Under Matrouh Conditions

Abstract

Onions are among Egypt's most significant vegetable crops, valued for local consumption and agricultural exports. Onions are highly valued for their distinctive pungent flavor and serve as a key ingredient in the cuisine of many regions worldwide. The scarcity of irrigation water is one of the main challenges limiting agricultural production in Egypt's arid and semi-arid regions. An experiment was
conducted over two consecutive winter seasons (2021/2022 and 2022/2023) on a private farm in the El Dabaa area, Matrouh Governorate, Egypt. The study aimed to evaluate the impact of different sandy soil covering techniques using plastic sheets: uncovered (UCS), half covered (HCS), and fully covered  (FCS), along with varying irrigation water levels (IR = 100, 85, 70, 55, and 40 % based on crop evapotranspiration). The experiment was carried out under both leaky pipe irrigation (LBI) and surface drip irrigation (SDI) systems to assess crop quality parameters, marketable yield (MY), seasonal actual evapotranspiration (ETa), water use efficiency (WUE), irrigation water use efficiency (IWUE), and the yield response factor (Ky) for the winter onion crop (Allium cepa L.). The results indicated that the winter onion crop's highest quality parameters and marketable yield were achieved under the FCS, IR = 100%, and LBI treatment in both seasons. In contrast, the lowest seasonal ETa values were recorded at 114.56 mm and 110.67 mm for the two seasons under FCS, IR = 40%, and LBI treatment. Additionally, the highest values of water use efficiency (WUE) and irrigation water use efficiency (IWUE) for the winter onion crop were 20.37 and 14.68 kg/m³ in the first season, and 21.21 and 15.08 kg/m³ in the second season, observed under FCS, IR = 55%, and LBI treatment. Finally, the lowest yield response factor (Ky) values were 0.09 and 0.11 for the two seasons under FCS, IR = 85 %, and LBI treatment. This study demonstrated that cultivating winter onions under FCS, IR = 55%, and LBI treatment could potentially conserve approximately 45% of the applied irrigation water while increasing the marketable yield of the crop by an average of 12% across both seasons compared to the control treatment (UCS, IR = 100%, and SDI treatment).