Onion Storage Trials at High Ambient Temperatures in the Republic of Yemen

Abstract

Onion storage trials were conducted at high ambient temperatures over two consecutive storage seasons in the Republic of Yemen. The onions were stored in specially designed wooden bins of approximately 5 t capacity, with positive ventilation. The trials were run at two sites during the first season to compare operation under differing ambient conditions (32°C and 75%r.h. compared with 26°C and 60% r.h.). The bins were relocated to a third site for the second storage season (28 to 34°C and 50 to 70% r.h.). Comparison of ventilation programmes during the first season indicated that a time-based regime, where the fan was set to operate at specific times each day, was the simplest and marginally most effective. Regimes based on full temperature and relative humidity control provided too little ventilation in the warmer more humid climate and resulted in severe losses. During the second season, overall losses after storage for 31 weeks were significantly reduced, compared with the traditional storage techniques of stacking sacks on pallets within an open-sided structure.