PRODUCTION AND WATER USE OF POTATO UNDER REGULATED DEFICIT IRRIGATION TREATMENTS

Field experiments were carried out for two consecutive seasons at the Agricultural Research Station of Abu-Graib, Baghdad - Iraq to study the yield of potato (Solanum tuberosum L.), under regular deficit irrigation. Soil moisture content with depth, potato yield, crop evapotranspiration (ET), water use efficiency (WUE) and crop water productivity (CWP) were measured. The irrigation treatments were, irrigate reestablishing field capacity when 60% of the available water was depleted (control), T1 was no irrigation during vegetative growth stage, T2 was no irrigation during tuberigation stage, and T3 was no irrigation during bulking and tuber enlargement. Results showed that the yield of potato were 34.5, 34.3, 28.2 and 30.2 T.ha^-1 for control treatment, T1, T2 and T3, respectively for the first season, while in the second one equaled 36.7, 36.2, 30.0 and 31.2 T.ha^-1. Values of cumulative ETa were 441-391 mm and 428.7-373.7 mm for the two seasons, respectively. The corresponding WUE were highest 8.33 and 9.21 kg.m^-3 under T1 treatment at vegetative growth stage of the two seasons. References ET were 494 and 472 mm for the two years based on Penman-Montieth equation.