storage

Grain storage systems

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Grain storage systems can be classified as either bag or bulk. A new storage system is hermetic storage, which can be either in bag or in bulk inside a hermetic container.

Bag storage system

In most parts of Asia grain is stored in 40-80kg bags made from either jute or woven plastic. Depending on the size of storage, these bags are normally formed into a stack.

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Properly stored bags

The hermetic IRRI super bag
When using bag storage consideration needs to be given to the following:
  • Jute bags should not be stacked higher than 4m and plastic bags 3m. Plastic bags are more slippery and the stacks will be less stable.
  • Bags should be stacked under cover e.g. under a roof, in a shed or granary or under water proof tarpaulins.
  • A one meter gap should be left between and around stacks and 1.5 meters clearance between the top of the stack and the roof.
  • Bags should be stacked on pallets or on an above ground structure to avoid the possibility of absorbing moisture from the floor.
  • Bags should not be stacked on a bed of rice husks or bags filled with rice husks, as these are difficult to keep free from insect infestation.
  • Bags should be stacked so that fumigation can be undertaken easily. The dimensions of the stacks should be set to facilitate sealing with a single fumigation sheet.
  • The efficiency of bag storage can be improved if a hermetic plastic liner bag like the IRRI Super bag is used inside the existing storage bag especially for seeds but also for commerical rice.

Some farmers use bag storage in outside granaries, which have been constructed from timber or mud/cement or large woven bamboo or palm leaves.

Bulk storage

Farm level bulk storage

At farm level grain is often stored in bulk in small outside granaries or in woven baskets or containers made from wood, metal or concrete, which are located under or inside the house. These storages vary in capacity from 200-1000kg.

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Wooden granary

Losses from insects, rodents, birds and moisture uptake are usually high in traditional bulk storage systems.

Commercial bulk storage

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Silos

The large export mills and collection houses sometimes use metal or concrete silos. These silos range in size from 20 to 2,000 ton capacity. Silos have the advantage that they can be more easily sealed for fumigation and less grain is spilt or wasted.Silos are not very common in Asia because of problems with moisture migration inside the silo which results in hot-spots and molds. 

Hermetic storage

Sealed or hermetic storage systems are a very effective means of controlling grain moisture content and insect activity for grain stored in tropical regions. By placing an airtight barrier between the grain and the outside atmosphere the moisture content of the stored grain will remain the same as when the storage was sealed. Biological activity inside the sealed container will consume the oxygen and as a result most insects will die. Hermetic storage provides moisture and insect control without pesticides.

For more information about hermetic storage see the Hermetic storage page.