IMPLEMENTS FOR AFTER-CULTIVATION The objects of after-cultivation are to destroy weeds, to keep the surface layers of the soil in a loose condition in order to conserve moisture, to aerate the soil, and in the case of such crops as cotton, maize and potatoes, to provide fine loose mould for earthing up.
(often called cultivators in America) of various types are used for these operations. For cereal crops horse-hoes fitted with A-shaped or L-shaped shares are used. The crop having been sown in rows, care must be taken in guiding the horse and steering the implement between them. The more elaborate hoes are fitted with a f ore-carriage and the shares can be raised by levers. For root crops, single, two or three-row hoes, often called scufflers or scarf Piers, are used, as a rule with a broad two-winged share in front with one or more L-shaped shares on each side. Some implements are fitted with tines to which detachable shares of various types for use in different operations can be fixed. For side-hoeing ridges, disk hoes may be used with skeleton rollers for keeping the implement in work. In America, implements for cultivating between the rows have been highly developed and are much more specialized than in Great Britain. Three or even more tines ("shovels") or disks may be used for each row and the implements may have seats, and levers for adjusting the tines or disks which may be set to move the soil either towards or away from the crop—an important consideration in the case of cotton and maize. Implements guided by runners or roller wheels, have also been specially designed to follow the listed furrow.
Thinners or gappers for thinning root crops have been de veloped but have not met with much success. The crop must be quite uniform if mechanical thinning is to give entire satisfaction, since the machine does not permit the operator to discriminate to the same extent as hand labour. The simplest form of mechan ical thinning or gapping is to run a horse-hoe either diagonally or directly across the rows. The special machines usually work along the rows and make use of rotating wheels of various types with blades or knives for cutting out bunches of plants as the implement moves.
In countries where intensive farming is practised various implements are used for grassland cultivation. Chain harrows (consisting of metal links with spikes or other projections connected together like a net), or brush harrows i.e., harrows with brushwood drawn through the frames in such a way as to form a kind of brush, or ordinary seed harrows are used in the spring for dragging out moss or matted undergrowth and dispersing any dung, molehills, worm casts, etc. Sometimes, particularly after frost, the flat roller (which is described above) is used to compress the soil around the grass roots and to level the surface. For aerating old pasture land, particularly where much coarse or matted under growth is present, cultivators with twisted knife tines are used, while rejuvenators utilize tines of various shapes to cut or tear the turf to admit air.
While at work machinery should receive constant attention to see that it is functioning properly, all bearings should be thoroughly lubricated, and any special instructions issued by the makers carefully followed. When no longer required in the fields machinery of even the simplest kind should be cleaned, placed under cover and all working parts protected from damp : id corrosion. If this is not done the life of the machine will be relatively short and its work unsatisfactory. Paint is a cheap and excellent preservative for both wood and metal and any damaged or worn paintwork should be restored before storage, and all bright and wearing parts thor oughly oiled or greased. Repairs should also be systematically carried out, preferably when work is not pressing, so that the machines are ready for use when next required.
