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What is the difference between a trench silo and a bunker silo?

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A large grain elevator and several metal silos stand on a farm surrounded by green fields, with hills and a partly cloudy sky in the background. — Farm building Grain elevator and silos on a small farm.

Both trench silos and bunker silos are types of horizontal silos used to store silage, but they differ primarily in their construction and placement relative to the ground level.12

Trench Silo: This structure is typically cut or dug into the ground, often utilizing a bank or slope. It is frequently used in regions with low rainfall.32
Bunker Silo: This structure is built aboveground. These are often constructed with concrete walls and have become a common sight in many rural areas worldwide for the storage of silage.24

Both types are parallel-piped in shape and may feature floors made of natural earth or concrete, with walls constructed from materials such as concrete, timber, plywood, or sheet steel. Regardless of the specific type, the primary purpose of these structures is to enclose and protect moist fodder, keeping it in a succulent and slightly sour condition suitable for livestock consumption.21