Integrating soil mulching and subsurface irrigation for optimizing deficit irrigation effectiveness as a water-rationing strategy in tomato production

Irrigated agriculture from now on should be implemented under water scarcity. Hence, this research was designed to determine the optimal interaction between irrigation water -rationing strategy (deficit irrigation), irrigation techniques, and soil mulching to improve water use efficiency and maintaining plant performance as well as yield productivity of tomatoes. The experiment was set up during the 2020-2021 and 2021-2022 growing seasons. Three factors were studied: two drip irrigation techniques, surface (SI) and subsurface (SSI) irrigation, and two irrigation rates, 100% ETc for full irrigation (FI) and 60% ETc for deficit -irrigation (DI) along with three treatments of soil mulching, bare soil (BS), organic mulch (OrM) and black polyethylene mulch (BPE). The results demonstrated that applying the absolute regular DI regime significantly reduced vegetative growth, fruit yield, and yield component along with water productivity. Also, it reduced the physiological function measures, and nutrient content of the tomato leaf. Meanwhile, applying the DI regime via the SSI technique and integrated with BPE soil mulching proved the best optimization of the DI negative effect followed by applying the DI regime through either SSI or SI technique combined with OrM or BPE soil mulching, respectively. As a result, it is advisable to use the integration of DI via the SSI accompanied by BPE soil mulching since this is considered a good method for conserving irrigation water from being lost by both evaporation and seepage out of the root zone improving water use efficiency without significantly reducing tomato yield.