Determination of Optimal Irrigation Scheduling for Onion (Allium Cepa L.) in Raya Valley, Northern Ethiopia

Abstract

Irrigation technologies that save water are necessary to assure the economic and environmental sustainability of commercial agriculture. Precision irrigation scheduling is critical to improving irrigation efficiency. A field experiment was conducted to evaluate the responses of onion to irrigation regime (when and how much) and to identify water productivity under optimal irrigation regime. The study was conducted for three non-consecutive years at Mehoni Agricultural Research Center, Raya valley, Ethiopia. Five irrigation scheduling (60% ASMDL, 80% ASMDL, 100% ASMDL (FAO recommended ASMDL), 120% ASMDL and 140% ASMDL were used. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Bomby Red variety of onion was used for this experiment. Results showed that onion marketable, total bulb yield and water productivity was significantly affected by irrigation scheduling. The highest marketable onion bulb yields of 27.45, 26.92 and 26.76 ton/ha were obtained from treatment 60% ASMDL, 80% ASMDL and 100% ASMDL, respectively.  The lowest yield of 24.45 and 24.32 ton/ha was obtained from treatment 120% ASMDL and 140% ASMDL respectively.  The highest water productivity (WP) of onion 5.81 kg/m³ was obtained from treatment of FAO recommended available soil moisture depletion level followed by +20 % FAO recommended ASMDL, while the lowest value of 4.74 kg/m³ was obtained from treatment -40% or 140% FAO recommended ASMDL. Therefore, based on the current findings, application of irrigation scheduling for onion in study and similar agro - climatic area and soil type application of irrigation at 100% ASMDL or FAO recommended gives highest bulb yield and water productivity.

Keywords: ASMDL, Irrigation scheduling, Onion, Water productivity

DOI: 10.7176/JNSR/9-20-02

Publication date:October 31^st 2019