Fo ^ for The Unit System. 



Plants J 



In the wholesale fertilizer trade some raw materials are 

 bought and sold on the "unit system." The unit is i per 

 cent., or 20 pounds per ton. 



Thus a lot of dried blood, containing 10.50 per cent, of 

 Nitrogen, equivalent to 12.75 P er cent - f ammonia, is said 

 to contain 12 24 units of ammonia, and, quoted at $2.50 per 

 unit, a ton will cost: 12 24 X$ 2 -5=$3 I -87^. 



A quotation of $1.50 per unit of available phosphoric 

 acid means $1.50 for each 20 pounds contained in the mate- 

 rial quoted. 



Illustration. A manufacturer offers dissolved bone 

 black guaranteed to contain 16 units of available phosphoric 

 acid, at $0.70 per unit : 1 6 X $0.70=$ 1 1 .20 per ton. 



Materials Used in Making Commercial 

 or Chemical Manures. 



M .. . Nitrate of Soda or Chili saltpetre occurs in 

 Nitrate of boda ... . , C. . , 



/-u-i. vast deposits in the rainless districts on the 



or Chili _,, / o i * i n 



Sal West coast or bouth America, chiefly in 



Chili, from whence it is imported to this 

 country for use in chemical manufacture and in agriculture. 

 As imported into the United States, Nitrate of Soda usually 

 contains from fifteen to sixteen per cent, of Nitrogen. Ni- 

 trate of Soda resembles common salt, with which and sodium 

 sulphate it is often adulterated. This salt is at once available 

 as a direct fertilizer, and being very soluble in water is there- 

 fore liable to be washed from soils. Whenever practicable it 

 should be applied as a top-dressing to growing crops, and if 

 possible the dressings should be given in two or three succes- 

 sive rations. 



Nitrate of Soda is usually applied at the rate of from 

 100 to 200 pounds per acre on land previously dressed with 

 farm-yard manure. To secure an even distribution, the Ni- 

 trate should be previously well mixed with from three to five 

 parts of fine loam or sand. 



Much has been said and written about Nitrate of Soda 

 exhausting the soil. This is all a mistake and is the outcome 

 of incorrect reasoning. Nitrate of Soda does not exhaust 

 soils. It does promote the development of the leafy parts of 



