POTASH FERTIIvIZERS 95 



potash is not available to plants and so a soil apparently rich in 

 potash will often be helped by a supply in artificial forms. The 

 addition of lime often increases the supply of available potash 

 in soils, by promoting certain favorable chemical changes. The 

 condition of the soil also influences the amount of available pot- 

 ash. Light sandy soils are more apt to be deficient in potash than 

 heavy soils. 



Forms of Potash. — A review of this chapter teaches us that 

 potash exists chiefly in three forms in fertilizer materials. 



. 1 , -J • ( Muriate of potash 

 As chloride m j gy,^.^.^ 



- . 1 u f • ^ Sulphate of potash 



As sulphate in | Double sulphate of potash and magnesia. 



As sulphate and chloride in Kainit (action same as chloride) 

 C Potassium-magnesium carbonate 



As carbonate in -s Wood ashes 



( Potassium carbonate. 



The form of potash is an important consideration in the pur- 

 chase of fertilizers, as potash in the form of chloride is injurious 

 to the marketable value of certain crops as tobacco, potatoes, 

 sugar beets, and oranges. Muriate of potash seems to make 

 potatoes waxy ; with sugar beets it seems to lessen the percentage 

 of sugar as sucrose ; for tobacco the flavor is spoiled for smoking 

 it sometimes forms calcium chloride in the soil which is not rel- 

 ished by plants. 



The form of potash does not seem to work any injury on crops 

 as legumes, grasses, corn, etc., and for such crops potash should 

 be purchased in its cheapest form. Muriate of potash diffuses 

 better in the soil than sulphate of potash. It should be under- 

 stood that actual potash (K2O) is not injurious to plants, but 

 the form or elements it is associated with are the cause of its 

 effect on crops. 



Fixation of Potash. — Potash is quickly fixed in the soil ; it re- 

 places the sodium and calcium in soils and forms compounds in- 

 soluble in water. The chlorides of potash are liable to render the 

 lime content of a soil deficient, as the chlorine unites with lime 

 and forms a soluble compound that is readily leached from the 



