PQTASK PAYS 81 



guarantee of 12.4 actual potash and contains potash, both 

 in the forms of sulfate and muriate. It contains salts of 

 magnesia and also common salt. Kainit can be used upon 

 the crops for which muriate of potash is recommended. 



Materials Furnishing Phosphoric Acid. 



Materials furnishing phosphoric acid in a highly avail- 

 able form are acid phosphate, dissolved bone and dissolved 

 bone black. 



Phosphoric acid in a less readily available form, is to 

 be had in bone meal and Thomas phosphate or basic slag. 

 The amount which is available will depend to a great 

 extent, upon how finely the material is ground. 



Ground bone meal contains, as a rule, from 25 to 28 

 per cent, of total phosphoric acid of which 6 to 8 per cent, 

 may be cons' dered available during the first year. It also 

 contains from 1 to 4 per cent, nitrogen. Dissolved bone, 

 acid phosphate and dissolved bone black usually contain 

 from 14 to 17 per cent, available phosphoric acid. 



Materials Furnishing Nitrogen 



The principal commercial sources of nitrogen are nitrate 

 of soda, supplying from 15 to 16 per cent of nitrogen: 

 sulfate of ammonia, 19 to 20 per cent, nitrogen, and dried 

 blood from 10 to 14 per cent according to the grade. Tank- 

 age, in addition to supplying from 7 to 9 per cent, nitrogen 

 usually contains about an equal amount of phosphoric 

 acid. Of many other sources of nitrogen somewhat less 

 in general use, we will mention dried fish scrap, containing 

 from 7 to 9 per cent, nitrogen and 5% to 7 per cent, 

 phosphoric acid, and cotton seed meal, containing 6% to 7 

 per cent, nitrogen and a small amount of phosphoric acid 

 and potash. 



