268 SOILS 



to irrigate corn, wheat, barley, and oats from 

 three to five times, oats requiring the most 

 water and barley least. In Colorado wheat 

 is irrigated but twice; but sufficient rain 

 usually falls in spring and early summer to 

 make the number of irrigations five or six if all the 

 water had to be applied from the ditch. Clover 

 and alfalfa are usually watered before growth 

 starts in the spring and once after each crop is cut, 

 applying 4 to 6 inches each time. Grass is com- 

 monly irrigated as often and as copiously as is 

 expedient without swamping the meadows usual- 

 ly every ten to eighteen days. Potatoes are not 

 irrigated until blossoming, then two to four times 

 thereafter. Fruit trees are irrigated less frequent- 

 ly but more deeply than field crops ; usually two to 

 six times a season, except citrus fruits, which 

 require more water. 



When water is plentiful the tendency is to over- 

 irrigate. This is dangerous; too much water is 

 as bad as drought. It keeps the soil cold, air does 

 not circulate in it and the beneficial germs of 

 fertility cannot thrive. The plants look yellowish. 

 If growing fruits, as peaches, they are forced to an 

 abnormal size and are watery, of poor flavour and 

 carry to market poorly. A good irrigator uses as 

 little water as possible. If growing tilled crops the 

 aim should be to make tillage take the place of 

 irrigation as much as possible, for water saved is as 

 good as water added, if not better. 



Winter irrigation is becoming quite common, 

 especially in parts of California and Arizona. 

 Wnen the water courses are dry in summer, but full 

 in spring after heavy rains, it is often practicable 

 to divert it to the land and allow it to soak deeply 

 into the subsoil, where it is stored against the 



