180 FARM-YARD MANURE. 



In the produce of his field the farmer actually sells his 

 land ; he sells, in his crops, certain elements of the atmo- 

 sphere, which come of themselves to his soil ; and with 

 them certain constituents of the ground, which are his 

 property, and which have served to form, out of the 

 atmospheric elements, the body of the plant, being them- 

 selves component parts of that body. In ahenating the 

 crops of his field, he robs the land of the conditions re- 

 quired for their reproduction. Such a system of husbandry 

 may properly be called a system of spohation. 



The constituents of the soil are the farmer's capital ; the 

 atmospheric nutritive substances are the interest of his 

 capital ; with the former he produces the latter. In selling 

 the produce, he alienates part of his capital and the 

 interest; in restoring the constituents of the soil to the 

 ground, he retains his capital. 



Common sense tells us, and all farmers agree, that 

 clover, turnips, hay, &c., cannot be sold off from a farm 

 without materially damaging the productive power of the 

 land for corn. 



Everyone wilHngly admits, that the removal of clover 

 is prejudicial to the cultivation of corn ; but that the 

 removal of corn should injure the cultivation of clover 

 is to most farmers an inconceivable, nay, an impossible 

 idea. 



Yet the natural connection and mutual relations be- 

 tween the two classes of plants are as clear as daylight. 

 The ash-constituents of clover and corn are the conditions 

 for the formation of clover and corn, and are identical as 

 far as the elements are concerned. 



Clover, just like corn, requires for its production a 

 certain amount of phosphoric acid, potash, lime, and 

 magnesia. The mineral constituents of clover are the 

 same as those of corn, plus a certain excess of potash, 



