FERTILIZERS 133 



large quantities of potash fertilizers have been shipped from 

 Stassfurt, Germany, where large deposits of potash salts have 

 been found and mined. Some of the principal forms of potash 

 fertilizers are: (1) kainit, (2) sylvinit, (3) muriate of potash, 

 (4) sulphate of potash. 



Kainit is composed of sodium chloride, magnesium chloride, 

 magnesium sulphate, and potassium sulphate. It contains about 

 12J per cent of potash. 



Sylvinit is similar to kainit, but most of the potash it contains is 

 in the form of a chloride, while in kainit most of the potash is in 

 the form of potassium sulphate. Sylvinit contains about 16 per 

 cent of potash. Both kainit and sylvinit improve the physical 

 character of the soil and have a valuable solvent effect upon phos- 

 phates. 



Muriate of potash is potassium chloride and contains about 50 

 per cent of potash. It dissolves readily in water and is easily 

 distributed through the soil. 



Sulphate of Potash is composed by volume of two parts of 

 potassium, one of sulphur, and four of oxygen. It contains about 

 50 per cent of potash and is valuable as a fertilizer for sugar 

 beets, tobacco, potatoes, and fruit. 



Sandy soils are generally lacking in potash and consequently 

 are greatly improved by the application of potassic fertilizers. 

 Clayey soils, on the other hand, are generally better supplied with 

 potash, and their need for fertilizers containing this element is not 

 so pressing. 



Phosphatic Fertilizers. These fertilizers contain phosphoric 

 acid in the form of phosphates of iron, lime, alumina, and other 

 metals. These phosphates fall naturally into two groups: (1) bone 

 phosphates, (2) mineral phosphates. 



Bone phosphates are derived, as we might expect, from the bones 

 of animals and contain phosphorus in the form of calcium phos- 

 phate. When bone is treated with hydrochloric acid, the calcium 

 phosphate is dissolved out and the soft animal matter remains; 

 when bone is burned, the organic matter is removed and the cal- 

 cium phosphate remains. Some of the principal forms of bone 

 fertilizers are raw bone, bone meal, bone dust, boiled or steamed 

 bone, bone black or animal charcoal, and bone ash. 



