90 THE PRINCIPLES OF AGRICULTURE. 



As the roots of plants are rapidly extended to con- 

 siderable distances in all directions, it is better, where 

 much fertilizing material is to be used, to distribute most 

 of it evenly through the soil, and apply but little to the 

 hill or drill. 



Farm Manure. The chief source of fertility, and that 

 upon which farmers mainly depend, is stable manure. 

 As it is generally impossible to raise good crops without 

 supplying some kind of fertilizer to serve as plant food, 

 the manure of the farm becomes a matter of the greatest 

 importance. The size and nature of the manure heap 

 often determine the profits of the farm. It is sometimes 

 called the farmer's " gold mine." 



Success in agriculture depends very largely upon an 

 understanding of the nature, the means of preserving, 

 and the proper methods of applying farm manure. 



Its Nature. It differs from the ordinary commercial 

 fertilizers in three respects : 



1. It contains all the elements of food required by 

 plants. As farm animals live upon the crops or plants 

 of the farm, it is evident that the manure will contain 

 the substances which come from these plants, and of 

 which they are composed, less so much as the animal 

 has assimilated, and converted into flesh, bones, wool, 

 milk, etc., and the carbon which has escaped with the 

 breath. 



Only a small part of the elements of food are thus 

 assimilated and retained by the animal in digestion. 

 The amount will depend upon the nature of the animal. 

 In the case of young, growing animals, cows giving 

 milk, or sheep producing large quantities of wool, the 

 proportion retained will be greater than in the case of 

 mature animals yielding no increase. It may be stated, 



