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 (6–8 in), whereas a subsoiler will break up and loosen soil to twice those depths.
Howse brand modular subsoiler mounted to a tractor
Modular subsoiler unit, unmounted with accessories
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commonly, the term is used to describe a farm vehicle that provides the power and traction to mechanize agricultural tasks, especially tillage, and now many more. Agricultural implements may be towed behind or mounted on the tractor, and the tractor may also provide a source of power if the implement is mechanised.
The Ford N-series tractor helped revolutionize modern mechanized agriculture with its Ferguson three point hitch
A modern Ukrainian tractor XTZ-243K
This Hayes WHDX 70-170 6×6 ballast tractor is also a form of tractor, as are artillery tractors and the power units which pull semi-trucks
1882 Harrison Machine Works steam-powered traction engine