384 SOILS 



SOURCES OF POTASH 



There are few commercial sources of potash; 

 the most important are wood ashes and the Ger- 

 man potash salts. 



Wood Ashes. Until the discovery of the potash 

 salts, this was the chief potash fertiliser. Wood 

 ashes are often leached with hot water to extract 

 the potash for soap-making and other purposes. 

 The ashes remaining contain only one- third as 

 much potash as before usually but 1 or 2 per cent. 

 besides 1| per cent, of phosphoric acid and 

 30 per cent, of lime. Unleached wood ashes, if 

 well cared for, should contain 6 to 9 per cent, of 

 potash, 2 per cent, of phosphoric acid, and about 

 32 per cent, of lime. Hardwood ashes are richer 

 than softwood ashes. 



Wood ashes are so variable in composition, ac- 

 cording to their source, impurities and care, that 

 one should buy them only on a guaranteed analy- 

 sis. A good sample is worth about twenty cents 

 a bushel for the plant food in it, which is almost 

 all immediately available. In addition, wood 

 ashes have an important indirect value, due to the 

 lime they contain. The price paid for them, how- 

 ever, should be based on their plant-food content 

 only. In this case the potash in them costs a 

 trifle more than that in the German salts; but the 

 indirect benefit of wood ashes is often so marked 

 that their great popularity as fertiliser is justified. 

 When they can be bought at about the same price 

 per pound of plant food, or a little more, as other 

 potash fertilisers, prefer the ashes. 



Besides wood ashes, cotton-hull ashes are a 

 valuable but limited source of potash; lime-kiln 

 ashes usually contain less than l per cent, of potash 



