lyo 



IRRIGATION FARMING. 



that too much will force its way through. One advan- 

 tage of these subsidiary canals is that it catches up the 

 leakage of the main canal and utilizes it for immediate 

 use, and at the same time avoids the discomfitures of 

 seepage waters on the lands to be irrigated. Some- 

 times these secondary canals are cemented, and they are 

 useful in governing the water for the furrows by means 

 of bulkheads. These bulkheads may best be fixed 

 permanently in position, and if supplied with sluice- 

 gates they are 

 ready for use at 

 all times, and will 

 last for years. Fix 

 these boxes in the 

 lower bank of a 

 .subsidiary ditch 

 at the head of the 

 < laterals — and they 



FIG. 48 — IMPROVED STEEL LAND GRADER, "^^.y alSO DC USCd 



in the laterals for 

 the furrows just as well. A very good arrangement of 

 this sort is described in Fig. 47. 



Preparation of Land. — Little inequalities in the 

 surface of a field give the irrigator more trouble in the 

 flooding system than do large hills. They are too 

 small to have any provision made for them except such 

 as may be extemporized with the shovel while the 

 water is running. When the surface can all be brought 

 to an even grade, work is greatly lessened, water is 

 economized, and the spotted appearance of the crop is 

 avoided. Grading fields on any large scale has hitherto 

 been impradlicable, because no machine was made 



