furrow slice slowly almost without breaking it, and is normally used for shallow ploughing (maximum depth). It is useful for grassland ploughing and sets up the land for weathering by winter frosts, which reduces the time taken to prepare a seedbed for spring sown crops. The digger mould board is short, abruptly curved with a concave cross-section both from top to bottom and from shin to tail. It turns the furrow slice rapidly, giving maximum shatter, deeper than its width. It is normally used for very deep ploughing ( deep or more). It has a higher power requirement and leaves a very broken surface. Digger ploughs are mainly used for land for potatoes and other root crops. The semi-digger mould board is somewhat shorter than the general-purpose mould board, but with a concave cross-section and a more abrupt curve. Being intermediate between the two mould boards described above, it has a performance that comes in between (approximately deep), with less shattering than the digger mouldboard. It turns an almost square-sectioned furrow and leaves a more broken surface finish. Semi-digger mould boards can be used at various depths and speeds, which suits them for most of the general ploughing on a farm. In addition, slatted mould boards are preferred by some farmers, though they are a less common type. They consist of a number of curved steel slats bolted to the frog along the length of the mould board, with gaps between the slats. They tend to break up the soil more than a full mould board and improve soil movement across the mould board when working in sticky soils where a solid mould board does not scour well. The land side is the flat plate which presses against and transmits the lateral thrust of the plough bottom to the furrow wall. It helps to resist the side pressure exerted by the furrow slice on the mould board. It also helps to stabilise the plough while in operation. The rear bottom end of the landslide, which rubs against the furrow sole, is known as the heel. A heel iron is bolted to the end of the rear of the land side and helps to support the back of the plough. The land side and share are arranged to give a "lead" towards the unploughed land, so helping to sustain the correct furrow width. The land side is usually made of solid