Pusa Bin is an improved grain storage structure developed by the Indian Agricultural Research Institute (IARI), New Delhi. It is essentially a modified version of the traditional mud storage structure commonly used in rural areas. The design incorporates a plastic lining and improved sealing to reduce moisture entry and air exchange, making it more suitable for safe storage of properly dried grains.
What is a Pusa Bin?
A Pusa Bin is a low-cost, farm-level grain storage structure constructed mainly from bricks, plaster and a plastic sheet. The plastic lining acts as an important barrier against moisture and helps improve the airtightness of the storage structure.
It can be used for storing cereals and other dry agricultural commodities when the grain is adequately dried before storage.
Construction of Pusa Bin
The construction of a Pusa Bin involves the following main steps:
Foundation:
A firm foundation of bricks or compacted earth is prepared. A 700-gauge plastic sheet is placed over it, extending at least 6 cm beyond all sides to provide moisture protection and better sealing
Walls:
About 7 cm thick mud bricks are laid over the plastic sheet, and the walls are raised to about 1.5–2.0 m height. The walls are finished and sealed with mud plaster.
Plastic lining:
Plastic sheet is provided along the inner surfaces of the walls and roof. It acts as a barrier against moisture and helps improve the storage conditions.
Roof:
A wooden frame supports the roof, which is generally made using burnt bricks and sealed with mud plaster. An opening is kept at the top for loading grain.
Loading opening:
A top opening of about 50 × 50 cm is provided for filling the bin. After loading, it is covered with plastic sheet and properly sealed to prevent the entry of air and moisture. Typical capacity of Pusa Bin mentioned in literature is approximately 1 to 3 tonnes.
Grain outlet:
An inclined steel or wooden pipe is fitted near the bottom of the bin. It allows grain to be removed conveniently by gravity.
Why Should Grain Be Properly Dried Before Storage?
A storage structure cannot correct the problem of excessively moist grain. If grain enters the bin with excessive moisture, it can undergo deterioration during storage.
High moisture can promote mould growth, grain heating, insect activity, deterioration of grain quality etc. Therefore, grain should be properly dried, cleaned and inspected before it is placed inside a Pusa Bin.
