Evaluation of agronomic characteristics of Potato under water deficit stress conditions using line-source sprinkler irrigation method and potassium fertilizer amounts

In order to investigate the agronomic characteristics of Potato under water deficit stress conditions using line-source sprinkler irrigation method and potassium fertilizer amounts an experiment was done in Khorasan Razavi Agricultural and Natural Resource Research Center during 2015-2016 as split plot design based on completely randomized blocks design. Water deficit levels at 0.75m from line-source (control), at 3.75m from line source (very light), at 6.75m from line-source (light), at 9.75m from line-source (severe deficit), at 12.75m from line source (very severe deficit) were considered as main factor and potassium levels included 0, 90, 180, and 270 kg.ha-1 K2O were as subfactor. Studied traits were included, tuber yield, percent of small, medium and big tuber yield, number of tuber per plant, average of tuber weight, plant height and stem number per plant. The results showed that water deficit stress levels had significant effects on total traits and potassium nutrition levels had same effects except percent of small and medium tuber yield and stem number per plant. Higher water deficit levels significantly decreased the tuber yield, tuber number per plant and average of tuber weight that in very severe deficit these traits reduced 92.29, 84.32, and 53.81 percent respectively. The highest tuber yield (17.92 ton.ha-1), tuber number per plant (7.94) and average of tuber weight (38.73 g) resulted in 270 kg.ha-1 K2O. The highest and lowest tuber yields were in control with 270 kg.ha-1 K2O and very severe deficit with 0 kg.ha-1 K2O.