239 FERTILIZERS 
use. Also, what sorts of manure are best for 
what special purposes. 
If the manure is carefully handled, that which 
is obtained from stock fed for soiling purposes 
—that is, especially to provide manure—is the 
best. It contains almost all the elements that 
the growing crops took from the soil. 
One well-fed dairy cow will produce 12? tons of 
manure in one year, says Prof. E. B. Vorhees, and 
this manure will contain about 117 pounds of 
nitrogen, 77 pounds of phosphoric acid, and 89 
pounds of potash. This much stable manure, 
if all the constituents are saved by housing and 
careful handling, will grow about 70 bushels of 
wheat and the accompanying straw. As all 
this nitrogen, phosphoric acid and potash have 
been drawn from the soil first in the crops fed 
to the cow, the only way to keep up the fertility 
of the soil is to return them to it. In the form 
of commercial fertilizers these would cost more 
than $30, or 20 cents per pound for nitrogen 
and 44 cents per pound for potash and phos- 
phoric acid. 
So if you keep one cow and feed her well, 
she will return to you almost her value in 
manure each year, to say nothing of the milk 
and butter your family can have. The family 
horse, as well as the cow, will give you valuable 
