Silo - Sairo (English spelling) silo

Japanese: サイロ - さいろ（英語表記）silo

A silo is a structure in which high-moisture feed such as pasture grass and green crops are packed, fermented with lactic acid, and stored to make silage. Required structural conditions are that it must be airtight, that the construction materials, especially the materials for the inner walls, must be acid-resistant, that it must have a drainage outlet (groove) to make it easy to pack and remove the silage, and that it must be able to prevent deterioration. For this reason, silos are often built in areas where it is difficult to make hay. The number of silos in Japan increased after World War II due to the rapid increase in the number of dairy cows raised.

[Nishida Tomoko]

Construction Materials

Concrete is strong and relatively inexpensive, making it the most common construction material for silos, but it is vulnerable to acids and its inner walls are easily corroded. Steel can be easily processed into shapes that maintain airtightness, and a thin plate of 3 to 6 mm thick is strong enough and lightweight, but it is vulnerable to acids and requires acid-resistant construction, making it expensive. Plastic materials are easy to maintain airtightness, acid-resistant, light, and easy to handle, so polyvinyl chloride and polyethylene sheets are used as covering materials for various silos, helping to improve the quality of silage, but they have the disadvantage of being easily torn. Fiber-reinforced plastics (FRP) are the most suitable material for silos, but they have some durability issues and are expensive. Other materials include concrete blocks for small rectangular silos, bricks, stones, and wood.

[Nishida Tomoko]

kinds

Depending on the shape and installation location, they are classified into vertical and horizontal types, above ground and underground or semi-underground types, etc. The main examples are as follows.

(1) Tower silo: A typical large vertical above-ground silo. Made of concrete, the circular silo is 1.5 to 6 meters in diameter and 5 to 18 meters in height (2.5 to 3 times the diameter). Material can be removed from either the top or the bottom.

(2) Airtight silos Made of steel or FRP, these are the most functional. They are 3 to 7.7 meters in diameter and 10 to 24 meters in height, and the silo remains airtight when the hatches at the top for loading and the bottom for unloading are closed.

(3) Bunker silo: A typical horizontal silo designed for free feeding of silage. A hole is dug above or below ground, the bottom and sides are constructed with concrete, and the raw grass is packed into it by thoroughly compressing it using a tractor or other tool, and the top is covered with a vinyl sheet.

(4) Trench silo This is an underground horizontal silo. It is a simple auxiliary silo in which a trench is dug in the ground, completely covered with a vinyl sheet, and the raw grass is packed into it.

(5) Stack Silo: A horizontal silo mounted on the ground, in which the piled raw grass is completely covered and sealed on the ground and above with vinyl sheets. It is used for short-term storage.

Silos are containers used to temporarily store grains imported from overseas as ingredients for compound feed. They are equipped with fumigation and ventilation systems, and can store food in good condition while preventing damage from insects and rodents.

[Nishida Tomoko]

Main types and structures of silos
©Shogakukan ">

Main types and structures of silos

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

サイレージをつくるため、材料の牧草や青刈り作物など高水分の飼料を詰めて乳酸発酵させ、貯蔵する構造物。構造上必要な条件は、気密性が保持できること、構築材料とくに内壁の材料は耐酸性であること、排汁口（溝）が設けられ、サイレージの詰め込み、取り出し作業が容易で、しかも変質が防止できることなどである。したがってサイロは、乾草をつくりにくい地域に多く建設される。日本のサイロは、乳牛の飼育頭数の急増に伴って、第二次世界大戦後に増加した。

［西田恂子］

構築材料

コンクリートは強度も強く、価格も比較的安く、サイロのもっとも代表的な構築材料としてあげられるが、酸に弱く内壁が侵されやすい。スチールは気密性の保持できる形状に加工しやすく、厚さ3～6ミリメートルの薄板で十分強度も強く自重が軽くてすむが、酸に弱く、耐酸施工を必要とするので高価になる。プラスチック材料は気密性が保持しやすく、耐酸性で軽くて扱いやすいので、塩化ビニルやポリエチレンのシートが各種サイロの被覆材などに用いられ、サイレージの品質向上に役だっているが、破れやすい欠点がある。繊維強化プラスチック（FRP）はサイロの材料として最適であるが、耐久性に多少問題があり、高価でもある。そのほか、小形角型サイロ用のコンクリートブロックや、れんが、石材、木材などがある。

［西田恂子］