Use:

A Plow share or Ploughshare is a component of a plough. It is the cutting or leading edge of a Mouldboard which closely follows the coulter (one or more ground-breaking spikes) when ploughing.

The ploughshare itself is often a hardened blade dressed into an integral mouldboard so making a unified combination of ploughshare and mouldboard, the whole being responsible for entering the cleft in the earth (made by the coulter’s first cutting-through) and turning the earth over which increases porosity & water retention capacity of the soil. It buries organic waste, weeds and parasites in the soil.