COMMERCIAL FERTILIZER. 



COMMERCIAL, FERTILIZER. 



Any substance that will supply the deficient ele- 

 ment or elements to the soil, in such a form that it is 

 available to the crop to be produced, is considered a 

 fertilizer. It is not uncommon to find an element in 

 the soil in sufficient quantity, but in such a form that 

 the crop cannot make use of it ; in other words, the 

 element is not available. 



COMPLETE FERTILIZER. 



A fertilizer that contains all three (nitrogen, potash 

 and phosphoric acid) elements is said to be complete. 

 The amount of any of the elements vary with the dif- 

 ferent brands and the different crops for which they are 

 to be used. The amount of any element in a special 

 fertilizer is governed by the amount of that element 

 removed from the soil by that particular crop. 



An incomplete fertilizer is one which is wanting in 

 any one or more of the fertilizing elements. These 

 are known either by the single element which they 

 contain, as potash, muriate of potash, nitrate of soda, 

 etc., or by so me trade name, as kainit, blood and bone, 

 guano, etc. 



Any one who uses a large quantity of fertilizer will 

 find it profitable to buy the simple fertilizers and mix 

 them to suit the particular crop. When only a few 

 tons are to be used, it is usually not profitable to mix 

 the fertilizer at home. A few words in regard to the 

 source of the fertilizer elements will be of value to us. 



SOURCES OF PHOSPHORIC ACID. 



A source of great commercial importance of this 

 fertilizer element is the phosphate rock of Florida and 

 South Carolina This rock contains a varying quan- 

 tity of phosphoric acid, and it is necessary to make an 



