192 HANDY-BOOK OF HUSBANDRY. 



of the necessity of adding manure to their soil, they belong to 

 one class ; — when the waning fertility of their land has compelled 

 them to seek its aid, to the other. 



When the demand for manure comes, (as it must, inevitably, 

 come in time, to all farms that are not occasionally inundated,) 

 the rules for its application, and the principles of its action must 

 apply to all alike. Of course one soil may be best improved by 

 one manure, another soil by a different manure, but — other things 

 being equal — in all localities. North and South, East and West, 

 the operation of manure and the necessity for its use are based on 

 the same laws, and are regulated by the relation between the 

 plant and the soil on which it grows. 



By " manure " we mean all substances which are applied 

 artificially to the soil to increase its ability to produce vegetable 

 growth. 



As all manures do not act in the same manner, they are some- 

 times classified as follows : — 



1. Nutritive : those whose own ingredients being taken up by 

 the roots of plants, go to form a part of their structures. 



2. Solvent : those which give to water a greater power to 

 dissolve the plant food already contained by the soil. 



3. Absorbent : those which add to the power of the soil to 

 absorb the fertilizing parts of other manures, of the water of 

 rains, and of the atmosphere circulating within it. 



4. Mechanical; those which improve the mechanical char- 

 acter of the soil ; — such as clay on sandy soil, and sand or peat 

 on heavy clays, and such as disintegrate the particles of the soil, 

 and make it finer. 



Probably no manure acts in any one of these capacities alone. 

 For instance, common salt not only gives up its own ingredients 

 to plants, but being dissolved in the water in the soil, it gives this 

 water greater power to dissolve other plant food from the surfaces 

 of the particles of earth, or from other manures added to it. It is, 

 therefore, to be regarded as both a nutritive and a solvent manure. 



Farm-yard manure, the universal fertilizer, is a direct source of 

 most valuable plant food; it produces, in its decomposition, 



