The diamond plow, so named because the inverted furrow slice is diamond-shaped rather than rectangular, is a recent innovation in moldboard plows and has a number of particularly interesting features: it has no coulters; the furrow wall is cut by the leading edge of the moldboard and instead of being vertical is curved; while the skimmers, which could be described as small plows fitted in front of the moldboard to take the trash off the top of the slice and push it into the furrow ahead of the ground.
It consisted of a six-foot curved wooden handle, with an iron point set at an angle of 120° to the handle, and a foot rest at the junction. The point was trodden into the ground, and the turf levered up with the handle.
The giant Rheinmetall trenching plow used in Germany in the first decade of the twentieth century was capable of breaking up subterranean veins of iron ore, throwing up boulders of up to 1650 lb in weight.
The Barrett, Exall and Andrews rotary cultivator produced in 1855 consisted of a revolving frame attached to the back of a steam engine. Various tools could be attached, for cultivating, harrowing and clod dividing, and it was claimed to be able to cultivate 6 acres a day to a depth of 1 ft.
The Hebridean cas crom or foot plow was used until recently on remote islands, and was ideal for stony noldboard, are fitted to the side of the moldboard. It is easier to pull than conventional designs.