Trenching
A term applied to the process of digging ground for the special purpose of increasing its depth for the better cultivation of various crops. It is chiefly practised in autumn, and the surface thrown up roughly for exposure to the weather. In commencing to trench a piece of ground, the soil, for about the width of 3ft., should be dug out a spit or more deep along one end, and wheeled to the opposite end, where it is intended to finish. The depth which should be taken out varies according to the nature of the subsoil; if this is unfit to bring to the surface, it should be dug and still left beneath. Another width should then be marked out, and the top spit of soil turned over take the place of that wheeled away, the bottom being, in its turn, treated like the first; and so on. When the soil is good enough to allow of the bottom spit being brought to take the place of the top, the first trench must be taken out to the full depth, and the bottom broken up. Trenching invariably deepens and improves garden land, but it is not always advisable to bring up the bottom soil at first; this is sometimes of a nature which causes actual harm to crops, and had better be left at the bottom below the limit which the roots reach. Trenching must, therefore, be practised with judgment. The bottom soil may always be loosened and dug, with advantage to that on the surface; and if some loose leaf mould or light manure is mixed into that beneath during the process, it will, in course of time, improve the whole bulk, and render it of a better description than before to a much greater depth.