Comparative effects of two water-saving irrigation techniques on soil water status, yield, and water use efficiency in potato

This study was conducted to compare two water-saving techniques: deficit irrigation (DI) and partial root-zone drying (PRD) with full irrigation (FI) on potato (Solanum tuberosum L.). These techniques were studied using drip irrigation in an arid region of Saudi Arabia in 2014 and 2015. Five irrigation treatments, i.e., FI (control treatment where the full amount of irrigation water was applied to both sides of the plant), DI70, DI50 (70% and 50% of the FI treatment, respectively, supplied to both sides of the plant), PRD70, and PRD50 (70% and 50% of the FT treatment, respectively, supplied to a single side of each plant in an alternating manner), were applied. The dry and wet sides of the plant in the PRD treatments were switched weekly. The soil water content was the highest in the FI treatment followed by DI70 and PRD70 and DI50 and PRD50 thereafter in 2014 and 2015. The fresh weight of the vegetative parts for both the FI and PRD70 treatments (average of 14.7 Mg ha(-1) and 11.9 Mg ha(-1), respectively) was significantly (p < 0.05) higher than that of the other irrigation treatments. The FI and PRD70 treatments increased (p < 0.05) the dry weight of the vegetative parts by approximately 48.3%-57.7% relative to the other treatments in 2014. The highest number of branches per plant occurred in the PRD treatments, and the lowest number was in the DI70 treatment. The DI and PRD treatments decreased (p < 0.01) the fresh and dry tuber yield compared to FI. The FI produced the highest number of tubers per plant. The DI treatments did not have a significantly lower irrigation water use efficiency (IWUE) compared to FI in 2014, whereas PRD had significantly (p < 0.01) lower IWUE than FI in both years.