36 



BULLETIN 720, U. S. DEPARTMENT OP AGRICULTURE. 



the Arkansas Valley (fig. IS). This means turning the water into the 

 field immediately after planting. On some farms, however, it is the 

 practice to irrigate the land in the autumn (fig. 19). 



Pig. 18.— Showing irrigation water in rows that were made smooth and even with the aid of a sled. 



Fig. 19.— Irrigating sugar-beet land in the autumn. The moistened soil responds more readily to the 



action of frost than dry soil. 



The available supply of water in this region depends largely upon 

 the water stored in reservoirs for irrigating sugar beets. Ordi- 

 narily the rivers do not carry much water that can be utilized for 



