USE OF MANURE8 147 



or cowpea. It will grow in a very poor soil and add 

 greatly to its store of nitrogen. 



The addition to the soil of stable manure accom- 

 plishes the sanu> purpose as plowing under green crops; 

 I it does more, for it adds to the soil some useful 

 ccmijtoumls of phosphoric ;i ml potash ami a host of 

 useful bacteria. Stable manure is both a special and 

 genera] manure; it adds to the soil oomponndi that 

 soon become available for plant food, and also grad- 

 ually improves the condition of the soil. Stable manure 

 is probably the most valuable of all manures, and may 

 be used to great advantage on most soils. It should 

 be regarded as one of the most valuable products of the 

 farm, and should never be wasted. 



Organic matter and moisture, however, are not the 

 only plant foods that may be lacking in poor soils; some 

 one or more of the mineral elements may be wanting. 

 Thus there are soils in which the supply of lime has 

 become exhausted, ami where this is the case the soil, 

 from the aecumulation of humus acids, usually becomes 

 BOUT. This acidity m;i\ he corrected by the application 

 of lime. Soils rich in decaying organic matter 

 improved by an application of lime. 



The total supply of phosphoric acid and potash in 

 soils is seldom exhausted, though roch cases do occur. 

 The available phosphoric acid and potash, on the other 

 hand, are often exhausted, and must !>»■ renewed either 

 hv the application of a fertilizer, or hx treating the soil 

 so as to render the insoluble compounds available. 



When a soil becomes worn and poor it should be 

 carefully examined, and, if possible, the cause of the 



