Irrigation management of potato based on soil profile water extraction

Efficient management of depleting water resources is important in order to enhance crop productivity and to attain high water use efficiency. The study aimed at identifying irrigation management practices, which could result in water savings through deliberate under irrigation. Field experiments were conducted at Hill Campus, Ranichauri, Tehri-Garhwal, Uttarakhand, India on potato crop (Kufri Chandramukhi) over a period of two years during the winter seasons of 2008-09 and 2009-10. The crop was planted in first week of November and harvested in the last week of March spanning approximately 150 days. Three irrigation treatments were maintained based on the maximum allowable depletion (MAD) of available soil water. The treatments were 20% (T1), 40% (T2) and 60% (T3) maximum allowable depletion of available soil water. No soil water stress was maintained at the initial stages of the crop development so as to allow the plant attain a healthy growth. Soil moisture content was measured by gravimetric method periodically in 0-15, 15-30 and 30-45 cm soil profiles. Soil moisture showed a cyclic temporal variation at all three selected soil depths. The magnitude of this variation was higher in 0-15 cm soil profile and decreased in 15-30 and 30-45 cm soil profiles in that order. This trend was observed at all schedules of irrigation. Field experiments revealed that irrigation schedule with 40% maximum allowable depletion of available soil water gave the maximum water use efficiency for potato crop. For scheduling of irrigation of potato crop, 0-30 cm soil profile should be considered as most of the required water to be extracted from this layer by the plant.