CHAPTER III. 



MANURES. 



Difference between natural vegetation and agriculture Necessity for 

 manuring. Farmyard Manure. Circumstances which influence its 

 character Losses in preparation Changes during fermentation 

 Its average composition Slowness of its effect Seaweed Guano 

 Fish Manure, Sulphate of Ammonium Nitrate of Sodium Soot, 

 Dried Blood, Powdered Horn, and Woollen Refuse Meat Meal, 

 Meat Guano Bones Oilcakes Phosphatic Slag and ground Phos- 

 phates Superphosphate Gypsum Lime, Chalk, and Marl 

 Potassium Salts Common Salt Application of Manures. Impor- 

 tance of thorough distribution Best time for application. Return 

 for Manure Applied. Increase from nitrogenous manures Effect 

 of residues of previous manuring. 



IN the natural vegetation of a forest or prairie the soil 

 suffers no diminution of plant food. The elements taken 

 from the soil are returned to it on the decay of the plants 

 which the soil has nourished, or on the death of the 

 animals which have fed on these plants. Under these 

 circumstances the surface soil becomes rich in carbon and 

 nitrogen, the quantity contributed by the atmosphere 

 at first exceeding, and then balancing, all losses. The 

 surface soil also becomes rich in the ash constituents of 

 plants, these being collected from the subsoil by the roots, 

 and left at the surface on the decay of the plant. A 

 virgin soil thus generally contains an abundance of plant 

 food, and will produce large crops without manure. 



As soon as land is brought under the plough the 

 oxidation of the organic matter previously accumulated 

 commences. The vegetable and animal produce of the 

 land are also now consumed off the soil which has reared 



