soluble Nitrate is formed from the less available and p? od t for 



less soluble Nitrogen of sulphate of ammonia, dried 



blood, cotton-seed meal, tankage, etc. It is due to 2I 9 

 the action of microscopic organisms, and all nitrogenous 

 fertilizers must undergo this process of Nitration before 

 plants can use them. 



Phosphoric Acid, one of the essential fertilizing 

 ingredients, is derived from materials called phosphates. 

 It does not exist alone, but in combination, most com- 

 monly as phosphate of lime in the form of bones and 

 Rock phosphate. Phosphoric acid occurs in fertilizers 

 in two forms — available and insoluble phosphoric acid. 



Superphosphate. — In natural phosphates the 

 phosphoric acid is insoluble in water and not available 

 to plants, except in the form of a very fine powder. 

 Superphosphate is prepared from these by grinding and 

 treating with sulphuric acid, which makes the phos- 

 phoric acid more available. Superphosphates are some- 

 times called acid-phosphates. 



Potash, as a constituent of fertilizers, exists in a 

 number of forms, but chiefly as sulphate and muriate. 

 The chief sources of potash are the potash salts, muriate 

 of potash, sulphate of potash. Canada wood ashes and 

 cotton-hull ashes are also sources of potash, as is also 

 Nitrate of Potash. 



Ammoniates. Nitrogenous Fertilizers. 



Per Cent. Lbs. Nitrogen 



Nitrogen. Per Ton. 



Nitrate of Soda 15 .00 300 



Cyanamid 17 . 00 340 



Dried blood 13 . 00 260 



Tankages 4.00 to 12.00 80 to 240 



Dry fish scrap 9 . 00 180 



Cotton-seed meal 6.80 136 



Barnyard manure . 05 1 



Castor pomace 5 .00 100 



Bone meal 3 . 00 60 



Phosphates. 



Per Cent. Lbs. Phosplioric 



Phosphoric Acid. Acid Per Ton. 



Superphosphate 14 280 



Ground bone 22 440 



Bone tankage 12 240 



Barnyard manure . 32 6 . 40 



