Storage performance of naturally ventilated structure for onion bulbs

A comparative study of naturally ventilated onion bulb storage structure and traditional in house floor storage was conducted in Fogera plain, Ethiopia to determine their performances. Onion bulb of Bombay Red cultivar was stored for 90 days in naturally ventilated storage structure and in house floor. The study was conducted from end of April to Jun 2011. Hourly temperature and relative humidity of ambient and storage environment were monitored and the physiological weight loss, sprouting percentage, rotting percentage and percentage of marketable bulbs on stored bulb were recorded every ten days interval. The observation has shown that the temperature profile of naturally ventilated storage structure has followed similar pattern with the ambient environment. Total percentage of bulb loss increases with storage period in both storage methods and lower values were observed in naturally ventilated structure than in house floor storage method. On the 50th day after storage, the overall bulb losses in naturally ventilated structures and in house floor storage were found to be 68.51% and 78.56% respectively.Keywords: Physiological loss, relative humidity, sprouting loss, temperature, weight los