SOILS AND FERTILIZERS. 377 



THE MANURES. 



Manures, in the narrow sense in which the term is here used, are 

 substances which, when put upon the land, increase its productivity 

 by virtue of the plant-food which they contain. This plant-food is 

 entirely of mineral origin and character, and though carbonaceous or 

 so-called organic matter is very important in modifying the properties 

 of a soil so as to render it better adapted for the support of plants, it 

 is in reality only the mineral matter of the soil which these absorb. 

 Plants, therefore, are manures in themselves, and having once gleaned 

 from the soil and taken up their needed amount of mineral matter, hold 

 it, of necessity, in the condition in which other plants may, without 

 difficulty, absorb it. The bulk of such manure, however, is great, and 

 the handling and hauling of it troublesome and expensive ; other forms 

 of it, the so-called mineral or chemical fertilizers, may with advantage 

 take its place, and it is of them that we speak here. 



These mineral manures, many brands of which are in the market, 

 are in reality only of three kinds, each containing one of the fertiliz- 

 ing materials that have been mentioned before ; all others are made 

 up from these, or are, at least, comparable to them as to price and value. 

 A compound or complete fertilizer is, on the whole, unscientific, and 

 though buying it may save the farmer some thinking, he is charged a 

 good round sum for the thinking which the manufacturer does for him. 

 No one supposes that all of the laud of a state, of a county, or even 

 a township, needs the same properties of plant-food in its fertilizers. 

 A complete fertilizer could, therefore, apply only to a perfectly sterile 

 land, and would have to differ with each crop raised on it. On any 

 other it must be wasteful, since, if one ingredient be in excess, it would 

 be left behind and not enter the plant, and if it fell short of the crop's 

 capacities for it, the others would be useless to the extent of their 

 exceeding it. Far better to apply potash, phosphoric acid and nitro- 

 gen separately as the needs for each may manifest themselves to the 

 farmer. To be successful in his avocation, he must be able to give the 

 same answer as the painter when questioned as to what he put in his 

 paints to make his picture so true and charming, viz., "brains ;" so the 

 farmer must put brains in his soil if he wishes it to respond without 

 waste to its full capabilities, and render his business — for business it 

 is — prosperous. 



Before discussing now the individual fertilizers, a summary state- 

 ment of the quantity of each per acre might be made, as far as the 

 question can be decided on general principles. In table 4 the weights 

 in pounds of the three important fertilizing materials removed per acre 



