426 



IRRIGATION PRACTICE 



and from the first irrigation may be done in the best 

 manner. 



Land may be leveled by any of the many machines on 

 the market. The regular scrapers or graders may be used 



FIG. 135. Concrete drop in ditch. 



for reducing the high points, and plank-levelers or floats 

 may be used for the final grading. (Figs. 127-129.) In 

 cutting down the high places, it is well to know something 

 of the subsoil. If the top soil is underlaid near the surface 

 with a lifeless clay it may not be wise to carry the grading 

 too low, or especially, to scatter the clay on the lower- 

 lying land. In such cases, slight grading through successive 

 years may be more satisfactory. For studying the sub- 

 soil, a soil auger is very useful. (Fig. 130.) 



254. Making farm ditches. After the layout of the 

 farm has been decided upon, the main supply ditches 

 placed, and the land leveled, the farmer may construct 

 the necessary laterals or farm ditches, fed by the larger 

 supply ditches. The location of the farm ditches must be 



