COMMERCIAL FERTILIZERS 



I 97 



Bone Fertilizers. Bones have long been a valu- 

 able and favored source of phosphoric acid. In ad- 

 dition to phosphoric acid they contain some nitrogen 

 which adds to their value. They are organic phos- 

 phates and are quite lasting in their effect on the soil 

 as they decay slowly. 



The terms " Raw Bone," " Steamed Bone," 

 " Ground Bone," " Bone Meal," " Bone Dust," 

 " Bone Black," " Dissolved Bone," indicate the 

 processes through which the bone has passed in 

 preparation, or the condition of the material as put 

 on the market and used on the soil. 



Ground bone, bone meal, bone dust, indicate the 

 mechanical conditions of the bones. 



The bones are sometimes ground " raw " just as 

 they come from the slaughter-house or kitchen, or 

 they are sometimes first " steamed " to extract the 

 fat for soap, and the nitrogenous matter for glue. 



Raw Bone. Analysis: Nitrogen, 2.5 to 4.5 per 

 cent. Available phosphoric acid, 5 to 8 per cent. 

 Insoluble phosphoric acid 15 to 17 per cent. 



Steamed Bone contains 1.5 to 2.5 per cent, of ni- 

 trogen, 6 to 9 per cent, of available phosphoric acid 

 and 16 to 20 per cent, of insoluble phosphoric acid. 



Steamed bone pulverizes much finer than raw 

 bone and decays more rapidly in the soil because 

 the fat has been extracted from it. 



Dissolved Bone. Ground bone is sometimes 

 treated with sulphuric acid to render the phosphoric 

 acid in it more available. It is then called dissolved 

 bone and contains thirteen to fifteen per cent, of 



