CHAPTER VIII 

 POTASH. 



Potash is the result of the oxidation of the element potassium, which is 

 one of the metallic elements. In former days all the potash available for 

 manurial purposes was that which is contained in the farm manures and in 

 wood ashes. These are still valuable sources so far as they go, but they are 

 totally insufficient for the demands of modern agriculture. It is a wonderful 

 fact in the economy of nature that stores are provided to come into use as 

 the demand for them arises. The vast deposits of coal were not discovered 

 so long as the forest met all the requirements of man for fuel, but as the de- 

 mand came the supply was at hand to meet it. Just so with the potash. 

 With the great call for this material for the feeding of plants on our long 

 cultivated soils, there was discovered a vast deposit of potash in the salt mines 

 of Germany, in the form of sulphates and chlorides of potash. These mines 

 are now the great source of the world's supply of potash, and it has been found 

 that the deposit extends over a much larger area there than was formerly sup- 

 posed, and that the supply is practically inexhaustible. Doubtless if the 

 German supply should fail there will be discovered other deposits, to redeem 

 the promise to mankind that seed time and harvest shall not fail. 



POTASH AN ESSENTIAL PLANT FOOD. 



Experiments, carefully conducted, have shown that potash is one of the 

 things which plants cannot grow without. In a soil or a solution entirely 

 free from potash a seed will germinate and grow to the extent of the potash 

 stored in the seed itself, but when that is used up the plant perishes. In the 

 cultivation of farm crops it has been found that potash is more slowly ex- 

 hausted from the soil than other forms of plant food, since its office mainly 

 consists in the building up of the woody structure and cellular parts of the 

 plant, and hence is found in the straw, corn stalks and other materials that 



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