sb. A kind of plow with no mould-board, used in plowed furrows to loosen the soil at some depth below the surface without turning it up.
1831. Jas. Smith, Thorough Draining (1843), 23. The Subsoil Plough … was designed … for the purpose of opening up the close subsoil of the farm of Deanston.
1834. Brit. Husb., I. 465. In this operation, the subsoil plough … would no doubt be found a valuable acquisition.
1859. Allen, New Amer. Farm Bk. (1884), 104. What is beyond it should be thoroughly broken up by the subsoil plow.
Hence Subsoil-plough v. trans., to use a subsoil plow upon; also Subsoil-ploughing vbl. sb., the use of a subsoil-plow.
1831. Jas. Smith, Thorough Draining (1843), 19. The charge of subsoil ploughing may be estimated at 24s. to 30s. per statute acre.
1840. Buel, Farmer’s Comp., 45. In subsoil ploughing, no portion of the subsoil is brought to the surface, but merely loosened, and pulverized.
1844. H. Stephens, Bk. Farm, I. 659. It is cheaper to subsoil-plough land than to thorough-drain it.
1848. Thackeray, Bk. Snobs, xxxi. I remember the conversations, O … how stupid they were! The subsoil ploughing;… the row about the representation of the county [etc.].
