34 



sixth, the mechanical effect which the manure has on the soil. 

 With reference to these, let us examine the following table, which 

 classifies the principal kinds of manures : — 



f 



Entire, 



Manures, 



f Barnyard manure, 

 j Other wastes, 



Composts, 



Mixed < Guano. 



Various ashes. 



f Oil cake, 

 j Malt germs. 

 ) Wash waters. 

 I. Sewage, etc. 



Various. 



Human excrements. 



Partial, . •< 



Concentrated, 



Nitrogen, 



-j Potash, . 



! Phosphoric acid, 

 (. Lime, 



f Nitrate of soda. 

 ) Sulfate of ammonia. 

 ) Ground meat. 

 (. Ground fish, etc, 



( Muriate of potash. . 

 ( Sulfate of potash, etc. 



!Raw phosphates. 

 Superphosphates. 



Various lime wastes. 



While many valuable manurial substances are mentioned in the 

 column at the right, only the first, barnyard manure, contains all 

 the elements of fertility, and at the same time the power to im- 

 prove the soil mechanically. This is why it is called the " entire " 

 manure. 



Barnyard manure deserves such a name more than any other 

 manure, but farmers are often sadly misled by such a designation ; 

 for it is supposed that, if this " entire " manure is applied to the 

 fields, no other manuring can be necessary. This designation 

 means simply that every one of the requirements of a manure is 

 found in barnyard manure, to a certain degree. But this degree is 

 unfortunately very small except in one particular. It brings into 

 the soil a large quantity of organic matter, which forms humus. 

 This increases the power of the soil to attract and retain moisture, 

 makes it more porous, promoting aeration and fermentation and 

 the bringing of all plant food into forms available for the crops. 

 For clayey or heavy soils it is of greatest value, and of least on light 

 and porous soils. Herein lies the chief value of barnyard manure. 



The analysis of a good half-rotted barnyard manure gives : — 



