Evaluation of Different Moisture Depletion Levels for Water Productivity, Yield and Tuber Size of Potato under Drip Irrigation

Abstract

A field experiment comprised of four different levels of management allowable depletion (MAD) of soil moisture for next irrigation to potato crop under drip irrigation was conducted during 2017-18 and repeated during 2018-19 at Water Management Research Farm, Renala Khurd, Okara, Pakistan. Cropwat 8.0 program was used to determine the interval and depth of next irrigation at 15, 30, 45 and 60% MAD of soil moisture. The experiments during both the years were organized in RCBD fashion with four replications. Irrigation to potato crop at 30% MAD level depicted the highest water productivity (17.28 kg/m3), followed by 60%, 15% and 45% MAD levels with water productivity values of 16.90, 16.63 and 14.60 kg/m3, respectively. The highest tuber yield was obtained when potato crop was irrigated at 60% MAD level (28.411 tons ha-1), followed by 30% MAD level (27.998 tons ha-1), 15% MAD level (26.736 tons ha-1) and 45% MAD level (24.081 tons ha-1). The maximum %age of medium sized tubers was achieved by applying irrigation to potato crop at 60% MAD level (65.70), followed by 30% MAD level (65.50), 45% MAD level (64.00) and 15% MAD level (60.50). The incidence of scab was found 2.50%, 2.75%, 3.25% and 3.75% in potato tubers at 15, 30, 45 and 60% MAD level, respectively indicating that the incidence of disease increased slightly with increase in MAD level.