100 Fertilizers 



Seaweeds as a source of potash. 



The flora of the Pacific Ocean includes many different 

 kinds of giant seaweeds which grow luxuriantly in the 

 coast waters from Alaska to Mexico. The giant kelp 

 groves have attracted much attention as a source of potash. 

 The ash of these weeds contains often as high as 30 per 

 cent actual potash. Great possibilities are presented by 

 these vast groves of seaweed because they may be har- 

 vested periodically and continue productive. Up to date, 

 however, no practical method has been developed which 

 enables the harvest and preparations for market of this 

 material at a cost sufficiently low to compete with the 

 German products. 



Fixation of potash. 



Potash, like phosphoric acid, is readily fixed in the soil, 

 though the chlorids with which it is combined when applied 

 may form soluble compounds that are readily leached from 

 the soil. For example, the chlorin combined with the 

 muriate may be combined with lime or soda, forming 

 soluble chlorids of lime or soda ; hence, heavy applications 

 of muriate of potash may result in the exhaustion of lime 

 in the soil. The fact that the potash is fixed, and that the 

 chlorids remain soluble, enables the application of a large 

 quantity, which might otherwise be injurious. That is, if 

 muriate, of potash is applied a considerable time before the 

 crop that may be injured by excess of chlorids is planted, 

 the chlorids are washed out, while the potash remains. 



Another point of importance should be observed in this 

 connection : the rapidity of fixation on many soils, espe- 

 cially those of an alluvial character, which explains the 

 recommendations frequently made to apply potash salts 



