SUGAR BEETS, POTATOES, ETC. 



311 



in the irrigated section. These and other crops should be 

 grown under irrigation as under humid conditions. Prac- 

 tically all of them may be grown successfully from the 

 first by remembering a few general principles: The soil 

 should contain much moisture at the time of planting. 

 The crops should 

 always be planted in 

 rows. As a general 

 rule it is best to irri- 

 gate in furrows. Irriga- 

 tion should be delayed 

 until the plant has 

 established its root- 

 system well and until 

 it really calls for water. 

 Irrigation should occur 

 every two or three 

 weeks. Water should 

 be applied liberally at 

 the time of flowering. 

 Where the rainfall is 



FIG. 85. Irrigated Egyptian cotton. 



from 12 to 15 inches 

 annually, a quantity of 

 irrigation water for the season, from 15 to 24 inches, is more 

 than enough to make sure of a good yield for any crop. 

 More than that is likely to cause deterioration of quality 

 and diminution in yield. Less than that often produces 

 the best yield. The crops that grow throughout the season 

 are watered more than those which have short growing 

 seasons. Crops that are leafy require more water than 

 those of small leaf surface. Crops planted closely together 

 use more water than those planted far apart. All hi all, 

 more depends ordinarily upon the soil than upon irriga- 



