CHAPTER IX 



PROPERTIES OF MANURES 

 "Manures are the food of plants, or the fertilisers of soils.'' 



Natural Manures. It is essential to replace 

 all the constituents in a soil that have been ex- 

 tracted from it by growing trees and shrubs. 

 This is one of the necessary conditions of a 

 proper system of cultivation. Trees and other 

 plants die from starvation — many a noble tree is 

 sacrificed for the want of proper manures ; look 

 at the cedars at Kew, and many other instances 

 might be enumerated. The soil does not contain 

 an inexhaustible supply of organic and mineral 

 substances in a suitable state for root-absorption. 

 It therefore becomes a necessity to apply the 

 proper manures for each tree, shrub or plant culti- 

 vated. 



Natural manures contain the solid and liquid 

 excreta of animals, which evolve heat and therefore 

 warm the land ; they also evolve carbon dioxide 



Q 2 



