THE WATER OF SOILS. 



237 



Surface Sprinkling. This method seems to be the closest 

 imitation of the natural rainfall ; and yet it is in practice about 

 the most wasteful and least satisfactory of all. It is difficult of 

 application on any large scale, from obvious causes; on the 

 small scale, in gardens and on lawns, its disadvantages become 

 amply apparent. As usually practiced, from a rose spout or 

 spray nozzle, the water falls much more abundantly than in 

 the case of any desirable rain, within the short time allowed by 

 the patience of the operator. If continued for a sufficient 

 length of time to soak the soil to the desirable depth, it com- 

 pacts the surface of the ground so as to render subsequent till- 

 age indispensable. To avoid this, amateur gardeners usually 

 restrict the time of application, repeating the same at frequent 

 intervals, sometimes daily. The result is that the very slight 

 penetration of the water either fails to reach the absorbent 

 roots, so that it is of little use to them, and is evaporated 

 by the next day's sun or wind ; or else it tends to draw the 

 roots close to the surface, where, unless the application of 

 water is actually made daily, they are sure to suffer from the 

 first intermission of the daily dose. In actual practice the 

 sprinkling method is therefore both inefficient and wasteful 

 of water, and exposes the plants to grave injury from any 

 cessation of the water supply. 



Flooding presupposes land either level or only slightly slop- 

 ing naturally, or rendered so artificially; usually by means of 

 the plow and horse scraper. 



Flooding by lateral overflow from large furrows, or ditches, 

 is very commonly practiced where the water supply is abundant 

 and large areas, such as alfalfa or grain fields, are to be irri- 

 gated. The overflow is regulated by portable check-boards, 

 proceeding from the highest points to the lowest, and leaving 

 each temporary dike in place until the ground is adequately 

 soaked or the water reaches the next furrow below. In heavy 

 ground the operation may have to be repeated to insure proper 

 depth of percolation. 



Check flooding necessitates more careful leveling, and the 

 throwing up of small dikes, either temporary or permanent 

 The costliness of the earth-work restricts the use of this 

 method materially, and the inconvenience caused in tillage by 



