RAINFALL AND EVAPORATION 



growing season, the man at Amarillo 

 would be working under conditions which 

 are practically twice as severe as those in 

 North Dakota. Under those conditions, 

 why are we justified in talking of precipi- 

 tation alone? What does precipitation 

 alone mean in connection with such fig- 

 ures as those? If we assume that the 

 precipitation required is in proportion to 

 the evaporation, then the man at Ama- 

 rillo, in order not to have to work harder 

 to conserve the moisture than the man in 

 North Dakota would need practically 

 twice the rainfall." In the well-known 

 desert region called the Staked Plains of 

 Texas, the evaporation is very much 

 higher. At El Paso it is 58 inches, and 

 at Yuma, Arizona, it is 56, while in New 

 Mexico at the boundary between upper 

 and lower California it reaches the 

 startling figure of 72 inches. The dry- 

 land farmer must therefore realize that 

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