mole drain
A channel in the subsoil (depth at least 0.45m) made by a specialized plough which has a ‘bullet’ of circular cross-section facing forward at the end of a narrow foot. The subsoil is deformed plastically by the bullet to leave the channel, while the upper layers of soil are ideally dry enough to be shattered by the passage of the foot.
This definition is abridged from A – Z of tree terms: A companion to British arboriculture.
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