OPTIMUM IRRIGATION SCHEDULES FOR TOMATO PRODUCTION UNDER FADAMA CONDITIONS IN THE GUINEA SAVANNAH REGION OF NIGERIA

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Department of Engineering

ABSTRACT
An experiment was conducted to determine the optimum irrigation schedules for tomato production under fadama conditions in Guinea Savannah region. The experiment consisted of five (5) levels of soil moisture replacement (100%, 80%, 60%, 50% and 40%) and three (3) levels of irrigation interval (3 days, 5 days and 7 days). The treatments were replicated three times in a Randomized Complete Block Design. Water applied to each basin was measured using cutthroat flume. The soil moisture depletion was monitored using a gypsum block (watermark sensor). The crop was harvested at maturity and the weight of the product measured to determine the yield in tons per hectare. The yield obtained ranged from 10.90t/ha to 28.22t/ha. The least yield was obtained from the treatment with 40% replacement and 7 day irrigation interval, while the highest yield was obtained from the treatment with 60% replacement and 5 day irrigation interval. The highest crop water use efficiency (CWUE) and irrigation water use efficiency (IWUE) were 68.33 kg/ha-mm and 54.60kg/ha-mm at 60% level of replacement. The least CWUE and IWUE were 35.58kg/ha-mm and 28.23kg/ha-mm both at 100% replacement. An economic analysis employed to determine the optimum irrigation schedule revealed that the optimum irrigation intervals for 100%, 80%, 60%, 50% and 40% replacements were respectively 10days, 10days, 11days, 12 days and 19days. The optimum irrigation amount for the season were 759mm, 633mm, 450mm, 405mm and 315mm for 100%, 80%, 60%, 50% and 40% replacements, respectively. It is concluded that irrigation that replaces 60% of moisture depleted every 5 days gives better results in terms of yield and water use efficiencies. However for maximum economic return, the optimum irrigation schedules observed in this study could be used.