Manures and Fertilizers 



character of the bone is secured, as the process makes the bone soft and 

 crumbly, and reduces it to a finer state of division than is usually accom- 

 plished by grinding". As the bone is also practically free from fat, it is more 

 useful as a source of phosphoric acid than the ground raw bone. Ground and 

 steamed bones are sold at $23.00 to $27.00 per ton. 



Bone black, or animal charcoal, after having been used in the sugar re- 

 fineries, consists chiefly of vegetable matter and moisture. It is variable in 

 composition, containing from 32 to 36 per cent, of phosphoric acid and a 

 small amount of nitrogen. It decays slowly in the soil, and its action extends 

 over a considerable period. Bone black is sold at $18.00 to $20.00 per ton. 



Phosphoric acid, applied in the form of raw or steamed bone, gives up its 

 nitrogen and phosphoric acid gradually, and its chemical and physical char- 

 acteristics are such that during the growing season it forms no compounds in 

 the soil more insoluble than itself. Bone is the only phosphatic material that 

 is now used without further treatment than simply grinding. 



The commercial acid phosphate, sometimes known as super-phosphate or 

 dissolved Carolina and Florida rock, contains from 14 to 15 per cent, of avail- 

 able phosphoric acid. It costs from $12.00 to $14.00 per ton, and is probably 

 the cheapest source of phosphoric acid that we have. 



The rock sulphates existing in South Carolina and Florida, sometimes 

 called Charleston Phosphate or Florida Phosphate, contain from 18 to as 

 high as 40 per cent, of phosphoric acid, which in its native form is largely- 

 insoluble, and must be treated with sulphuric acid before the phosphoric acid 

 is made available. When so treated it is nearly as valuable as the various 

 bone phosphates above mentioned, and is sold at $12.00 to $14.00 per ton. 



Potash 



The third important constituent of plant fertilizers, potash, is considered 

 of less relative importance to plant growth than either nitrogen or phosphoric 

 acid, as all good soils are, naturally, much richer in potash, and a less amount 

 is removed from the soil in plant growth than of either nitrogen or phos- 

 phoric acid. It is deemed, however, a necessary fertilizer constituent, and 

 essential for use upon light sandy soils, or for peaty meadow lands. It is 

 rated as particularly valuable in the building up of worn-out soils, as it is 

 thought to contribute largely to the growth of nitrogenous gathering plants. 

 The various sources of potash are as follows : 



First. Sulphate of potash, which contains 48 to 53 per cent, of available potash 

 and is probably the cheapest form in which potash can be secured. It can be purchased 

 from dealers in fertilizing materials, at prices ranging from $44.00 to $48.00 per ton. 



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