254 SOILS 



the soils of few farms are exactly alike, or have been 

 cropped alike. Irrigation has been practised 

 for nundreds of centuries, yet there is no 

 generally accepted body of information on the best 

 way to use water. This must be left largely to the 

 judgment of the farmer. So there are good and 

 there are poor irrigators, according to ability to 

 judge correctly the nature of the soil and the needs 

 of the crop. One man is able to make an inch of 

 water go twice as far as another. Some souse 

 their crops and puddle their land; others know 

 how to let the soil dry out and sweeten until the 

 critical time comes when the crop would suffer if 

 water were not added. Like tillage, irrigation is a 

 matter of judgment, not of rule. 



The principal methods of applying water are by 

 flooding, by furrows, and by sub-irrigation. The 

 method of applying water to the land is governed 

 by the kind of crop and the texture of the soil and of 

 the subsoil. If the soil is coarse-grained water will 

 sink down rapidly and much will be lost by seepage 

 if it is allowed to stay upon the soil long in the same 

 place, as in furrow irrigation. Coarse-grained 

 soils should be flooded, if expedient. 



FLOODING 



The simplest way to use water is to spread it 

 over the surface, as a river overflows its banks. 

 If the land is fairly level this is the cheapest 

 method of wetting a large field before it is plowed 

 for planting and also for watering land used con- 

 tinuously for grains, grasses, clovers and other 

 crops that are not tilled. But an almost perfectly 

 level field is rare; so, in the contour check system 

 of flooding, it is usually necessary to throw up low 



