244 DRY FARMING 



every alternate row only, and turn it off just as soon as 

 it gets through so as not to let the ground soak up any 

 more than is necessary. As soon as the ground dries suf- 

 ficiently the land should be given a shallow cultivation. 



Fig. 87. — Furrow System of Irrigation. 



About ten days after the first irrigation, the second 

 should be given. This time the water may be run down 

 between all the rows and should be allowed to remain 

 running until the land is well wetted. After irrigation 

 has once begun, the land should never be allowed to dry 

 up completely. Unless heavy showers intervene, it will 

 be found necessary to irrigate about every ten days in 

 order to maintain a moist condition. After each irriga- 

 tion as soon as the surface of the soil dries sufficiently it 

 should be given a shallow cultivation. If for any reason 

 after irrigation has once begun the land is permitted to 

 become quite dry the potatoes should not be irrigated 

 again. If they are, a second growth is almost certain to 



