Types of silo


  • The kind of silo and the choice of construction material should be determined primarily by economics. Silos may be classified as follows:
  • Conventional upright (tower)silos
    • Concrete stave (thin strips of concrete set edge to edge to form the wall).
    • Wood stave
    • Tile block
    • Brick
  • Gastight (oxygen - limiting)silos
    • Concrete stave
    • Brick
  • Pit silos
  • Horizontal silos
    • Trench silos (below ground level)
    • Bunker silos (above ground level)
  • Temporary silos
    • Plastic or polythene bag silos
    • Modified trench - stack silos

Conventional upright (tower) silos

  • All upright silos are circular in shape and equipped with a series of doors about 2 sq. ft. approximately every 6 ft. up on one side of the silo. These are closed as the silo is filled and opened as the silo is emptied. Recent developments in construction of tower silos have been made in bottom unloaders with large diameter features (24-30 ft.). However, the size varies from about 12-20 ft. in diameter and 40-80ft. in length. For effective preservation of silage, the forage should contain between 25 and 35 per cent dry matter.

Gastight silos or airtight or sealed silos

  • These silos resemble conventional tower silos, but they are more expensive because of their construction to make the tower completely free from oxygen. Gastight silos are designed for forages having as high as 50-75 per cent dry matter or for the storage of high moisture grain containing 60-75 per cent dry matter.

Pit Silos

  • A pit silo is shaped like the tower silo, but inverted into the ground. It resembles a well. This type of silo can be made only in places where the water table is low enough (in semi- arid or in arid regions) that the silo will not fill with water.
  • In comparison with tower silos, pit silos have the following
      • They are never damaged by storm and
      • Require less reinforcing.
    • Disadvantages are
      • They are dangerous, due to the frequent presence of suffocating Co2 and
      • Considerable work is involved in removing the silage.

Horizontal Silos

Trench Silo

  • At a comparatively low cost this type of silo can be constructed quickly. It is most popular in areas where the weather is not too severe and where there is good drainage. A trench silo should be wider at the top than at the bottom, and the bottom should slope away from one end so that excess juices will drain off if material with high moisture content is ensiled.
    • Low initial cost and ease of construction.
  • Disadvantages
    • In comparison with the tower type it will require larger space to seal. When filling is completed, the top should be carefully sealed by polyethylene, plastic or by wet straw mixed with mud or by saw dust to make it air tight.

Bunker silos

  • As a labour saving measure, bunker type of silos above the ground (for slightly recessed) usually with concrete floors are generally catching the attention of many farmers.

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Last modified: Friday, 26 August 2011, 10:50 AM