CAMPBELL'S SOIL CULTURE MANUAL 123 



.CHAPTER XVI. 



EVAPORATION. 



In connection with the percolation of the water down 

 through the soil and the capillary movement of the water 

 upwards, there is the all-important topic of evaporation. 



It is highly important to the farmer living in the semi- 

 arid region to know all about evaporation, for it is by 

 evaporation rather than by under drainage that the larger 

 part of his water leaves him. 



When one understands perfectly the effect of evap- 

 oration and how it operates to remove water from the 

 soil he is in a position to better understand why it is that 

 there can be so much conservation of the moisture in the 

 soil that the land of the semi-arid belt becomes in fact 

 better fitted for good crops than the land of the more 

 humid sections. It is a common remark among those 

 who but little understand the situation that if there was 

 only a little more rainfall in the semi-arid region it would 

 be the ideal farming country. They say that all the coun- 

 try lacks is enough rainfall to provide all the water neces- 

 sary. This is a superficial view. It does not take into 

 account the main elements. 



It is true that if we could always have here in the semi- 

 arid country just the right amount of rainfall, and have 

 it at the right time, we would have no trouble in raising 

 good crops. It would be very nice indeed to have this 

 condition. We would have the tropics beat badly, and 

 our people would have time for bull fights and things like 

 that while they were just waiting for the crops to mature- 



