Field experiments were conducted during the dry seasons of 2006/07 and 2007/08 at the Teaching and Research Farm of the College of Agriculture, Zuru, Kebbi State, Nigeria. The objective was to investigate the response of onion to irrigation interval and plant population density. The treatments consisted of factorial combination of four irrigation intervals (3, 6, 9 and 12 days) and five plant population densities (160,000, 200,000, 250,000, 350,000 and 500,000 plants/ha), corresponding to 25x25, 25x20, 20x20, 20x15 and 20x10 cm spacing respectively. The treatments were laid out in a split plot design with three replications. Irrigation interval was allocated to the main plots and population density to the sub plots. Results reveal that mean bulb diameter, mean cured bulb weight and onion yield in both trials and the combined analysis were significantly (p < 0.05) favoured by irrigation intervals at 3 and 6 days. Lower plant densities (160,000 and 200,000 plants/ha) increased both bulb diameter and cured bulb weight but decreased total yield. The result of the research concluded by recommending 6 days irrigation interval and plant population density of 500,000 plants/ha for maximum onion yield in the study area.
Keywords: Onion, irrigation, population, Northern Guinea savanna, Nigeria
Nigerian Journal of Basic and Applied Science (2011), 19(2):241- 247