Snapshot

A subsoiler or flat lifter is a tractor-mounted farm implement used for deep tillage, loosening and breaking up soil at depths below the levels worked by moldboard ploughs, disc harrows, or rototillers. Most such tools will break up and turn over surface soil to a depth of 15–20 cm (5.9–7.9 in), whereas a subsoiler will break up and loosen soil to twice those depths. A subsoiler is a tillage tool which will improve growth in all crops where soil compaction is a problem. In agriculture angled wings are used to lift and shatter the hardpan that builds up due to compaction. The design provides deep tillage, loosening soil deeper than a tiller or plough is capable of reaching. 

The subsoiler consists of three or more heavy vertical shanks (standards) mounted on a toolbar or frame with share bolts. They can be operated at depths of 45–75 cm (18–30 in) or more. A ripper normally runs 35–45 cm (14–18 in) deep. Shanks are curved and have replaceable tips. Each shank is fitted with a replaceable point or foot, similar to a chisel plough, to break through the impervious layer, shattering the sub-soil to a depth of 45–75 cm (18–30 in). Subsoiling is a slow operation and requires high power input: 60 to 100 hp to pull a single subsoil point through a hard soil. Agricultural subsoiler implements will have multiple deeper-reaching blades; each blade is called a scarifier or shank.

One type of subsoiler has a torpedo-shaped tip and is called a mole plough because the tip describes a path much like the burrow that a mole creates. Mole ploughs are used to create tile drainage, with or without tiles or tile line added. A form of this implement (with a single blade), a pipe-and-cable-laying plough, is used to lay buried cables or pipes, without the need to dig a deep trench and re-fill it.