112 



SOILS AND FERTILIZERS 



It will be readily seen that in order to obtain all 

 three elements it will be necessary to make a fertilizing 

 mixture. For instance, to obtain the 10 pounds of 

 nitrogen needed for one acre, about 65 pounds of Chile 

 saltpeter will be required; for 15 pounds of soluble 

 phosphoric acid, it will take 100 pounds of bone black, 

 and 160 pounds of kainit or 40 pounds of muriate of 

 potash to furnish the potash needed. 



Note. In mixing fertilizers care should be taken that combinations 

 are not made that will release any food element that will be lost in the 

 air or that will lock up in chemical combinations food elements so that 

 they are not available. Figure 42 will aid in avoiding error. 



Superphosphate 



Thomas Phosphate 



Potash Salts 



Nitrate of Soda 

 FlG. 42. 



Substances connected by thick line must not be mixed together. Substances connected 

 by double line must be mixed only immediately before use. Substances connected by single 

 thin line may be mixed together at any time. After Geekens. 



Application. -- The manner of applying commercial 

 fertilizers depends upon their form, whether soluble 

 or insoluble. If the former, they may simply be scat- 

 tered over the surface of the land, for the rains will 

 cause them to mix with the soil. If insoluble, they 

 should be mixed with sand or ashes, spread as evenly 



