IRRIGATION

(Lat.) The art of watering lands artificially, and by means of surface drains or channels, as contrasted with watering by manual labour. In Britain, and in analogous climates, irrigation is almost exclusively applied to gra lands; but in warmer climates, such as those of Italy, Syria, India, ., irrigation is considered as e ential to the production of large crops in every description of field and garden culture. When any surface is to be irrigated, the supply of water which is to be used for this purpose is conducted to the highest part of that surface, and from thence it is led over it in open gutters, so as to run very slowly, and sink into the earth as it proceeds. As in general no very great extent of surface can be irrigated at once, different parts of a field or farm are irrigated in succe ion; and in countries where this practice is universal, it often happens that one source of of supply is common to two or more farms, the occupiers of which have it on alternate days. In the south of France and Italy, abundant crops cannot be produced without irrigation. Even the potatoe crop and madder are irrigated in the neighbourhood of Avignon; and in Tuscany wheat, maize, beans, turnips, and every other crop that can be sown in drills in the fields, is watered from artificial channels. The practice is as old as human civilization, and some of the first machines which we read of in history are those for raising water from the Nile for irrigating the lands on its banks. Water, in short. Is to the agriculture of warm climates, what manure is to the Rr 3 [s. 626]