Effects of different surface and subsurface drip irrigation levels on growth traits, tuber yield, and irrigation water use efficiency of potato crop

Increased water demands and climate change have reduced agricultural water resources in areas that experience water shortages. Therefore, a field experiment was conducted in an arid region of Saudi Arabia to evaluate the effects of two drip irrigation systems [surface (DI) and subsurface (SDI)] and three irrigation levels [100%, 70%, and 50% of crop evapotranspiration (I-100, I-70, and I-50, respectively)] on the growth traits, tuber yield, and irrigation water use efficiency (IWUE) of potato (Solanum tuberosum L.) during the 2017 and 2018 growing seasons. theta(v) was 13.74 and 23.85% lower under the DI system and 11.90 and 24.14% lower under the SDI system with the I-70 and I-50 treatments, respectively, than with the I-100 treatment, and was also lower under the DI system than under the SDI system. The fresh and dry vegetative parts of the plants were heavier with the I-100 treatment under the SDI system than with the I-70 and I-50 treatments under the DI system, and the leaf area indexes were also significantly lower with I-70 and I-50 than with I-100 but were not affected by the irrigation system. The fresh and dry tuber yields were lowest with the I-50 treatment (23.97 and 3.93 Mg ha(-1), respectively), followed by I-70 (28.61 and 4.98 Mg ha(-1), respectively), and I-100 (34.43 and 6.67 Mg ha(-1), respectively) and were higher under the SDI system than under the DI system. By contrast, IWUE was highest with the I-50 treatment (6.49 and 7.02 kg m(-3)) and lowest with the I-100 treatment (5.62 and 5.85 kg m(-3)) under the DI and SDI systems, respectively. These findings indicate that full irrigation (I-100) with the SDI system maximizes potato yield but decreases IWUE, whereas integration of the SDI system with deficit irrigation is effective in improving water productivity due to less water being consumed, allowing these practices to be used under scarce water conditions.