Superphosphates Potash 93 



are followed by heavy rains. The fact that the fixing 

 power of soils practically prevents the loss of phosphoric 

 acid should, however, not be used as an argument in favor 

 of the careless use of superphosphates. 



POTASH SALTS 



Until the discovery of the mines of crude potash salts in 

 Stassfurt, Germany, in 1859, and which have been worked 

 since 1862, the chief source of potash for farm plants, other 

 than that contained in farmyard manures, was wood-ashes. 

 The supply from this source now, however, is sufficient to 

 meet all immediate as well as future demands, since the 

 deposits are practically inexhaustible, though notwith- 

 standing the abundance of the supply and the improve- 

 ments made in the methods of utilizing the various salts, 

 other than potash, contained in the deposits, it is the only 

 fertilizer constituent which has remained practically con- 

 stant in price during the past fifteen years. In this period 

 not only have wide fluctuations occurred in prices of nitro- 

 gen and phosphoric acid from the different sources, but 

 they are much lower now than formerly. 



The importance of potash as a constituent of fertilizers. 



It has been attested that potash is of relatively less 

 importance than either nitrogen or phosphoric acid, inas- 

 much as good soils are naturally richer in this element, and 

 because a less amount is removed in general farming than 

 of either nitrogen or phosphoric acid, as the potash is 

 located to a less extent in the grain than in the straw, 

 which is retained upon the farm. It is, however, a very 

 necessary constituent of fertilizers, being absolutely essen- 

 tial for those intended for light, sandy soils and for peaty 



