8 FERTILIZERS IN THE WEST 



manure slowly liberate phosphoric acid from the rock phos- 

 phate and thus make it available. 



Potash : The only commercially important source of this 

 fertilizing element are the German potash mines which 

 furnish potash in a water soluble and immediately available 

 form. The crude salts, kainit and manure salt, containing 

 12.4 and 20 per cent of pure potash, respectively, are largely 

 used where freight rates are low or where they offer special 

 advantages, as kainit does as a remedy against cotton rust. 

 Muriate of potash and sulphate of potash contain about 50 

 per cent of pure potash; the muriate may be used for most 

 crops, while the sulphate is preferable for tobacco, orange 

 trees and potatoes. 



In consideration of the fact that potash, phosphoric acid 

 and nitrogen are of so much importance in the nutrition of 

 plants it is not to be wondered at' that their use in the form 

 of fertilizers has given such excellent results wherever the 

 right kind of fertilizer has been given a fair trial. In the 

 following chapters we shall demonstrate by the results of 

 actual field experiments that fertilizers are just as necessary 

 and as profitable in regions of low rainfall as they are in the 

 humid zone. 



Fertilizers Are Profitable in Dry Regions as Well as in 

 Humid Sections. 



There is an idea generally prevailing in the Western 

 States that while it may be profitable and necessary to use 

 commercial fertilizers in the humid sections of the country, no 



