Modern NHRDF onion storage structure under sub-tropical conditions

In India onion is produced in three season's kharif, late kharif and rabi, in which rabi harvest have good keeping quality and can be stored for longer period up to 5-6 months. Over a period of storage, there is a gain of three to four times profit in market due to non-availability of onion. Hence, the storage of onion is very essential to maintain regular supply to the consumer till November. Due to improper storage, more losses arise in farmer's storage method due to higher sprouting, rotting and physiological loss in weight, which leads to heavy stress on both demand and supply resulting in a steep rise in the price. Scientifically developed storage facilities will help in checking the supply volatility and rise in onion prices. Under existing ambient conditions, NHRDF has developed a ventilated conventional onion storage structure providing proper aeration and ventilation without any control on temperature and humidity. This storage structure is popularized in major onion growing states in India. Recently, the NHRDF has developed an improved storage structure designed to maintain the constant temperature and relative humidity throughout the storage period. After six months of storage, highest quality bulb recovery (21.40 ton), with lowest rotting (0.69%), physiological loss of weight (13.83%) and total loss (14.52%) were recorded in NHRDF improved onion storage structure. Due to highest bulb recovery, highest net returns are obtained. While in NHRDF conventional ventilated storage structure, moderate quality bulb recovery (16.70 ton), sprouting (2.50%), rotting (10.10%), physiological loss of weight (20.80%) and total losses (33.40%) were recorded. The lowest quality bulb recovery, highest sprouting, rotting, physiological loss of weight and total loss were recorded in farmer's storage structure. Apart from these, NHRDF improved onion storage structure has several advantages over cold storage structure, conventional ventilated storage structure and farmer's storage structure.