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Webster 1913 Edition
Subsoil
Sub′soilˊ
,Noun.
The bed, or stratum, of earth which lies immediately beneath the surface soil.
Subsoil plow
, a plow having a share and standard but no moldboard. It follows in the furrow made by an ordinary plow, and loosens the soil to an additional depth without bringing it to the surface.
Knight.
Sub′soilˊ
,Verb.
T.
To turn up the subsoil of.
Webster 1828 Edition
Subsoil
SUB'SOIL
,Noun.