PER TILIZERS. 527 



returned also to the field. Manuring by fallows and by animal 

 manures, are merely different methods of returning to the soil a 

 portion of its own product, and so reducing to the lowest prac- 

 ticable point the deportation of the elements of fertility which 

 are sold off the farm. It is true that the fallow plant, during its 

 growth, increases the amount of combined nitrogen in the soil, 

 and thus, if wholly returned to the soil, increases the aggregate 

 fertility. But if the products of the soil be fed out to animals, 

 there will be retained by the animals some of the elements of 

 fertility ; and some further loss necessarily occurs in handling 

 the manure. So the feeding of animals, unless a considerable 

 portion of their food be bought and brought onto the farm from 

 outside sources, depletes the soil to some extent, though by feed- 

 ing out the product of the land upon the land, depletion will be 

 minimized. A complete system of fertilization must embrace a 

 fallow-crop ; the feeding of animals, not only with as much as 

 possible of the products of the farm, but also with as large an 

 amount as possible of bought feed ; and the fallow and farm- 

 yard manure so produced must be supplemented by the skilful 

 use of commercial fertilizers. The formula is in the order of 

 importance : green fallows, animal manures, and commercial 

 fertilizers. 



But a scientific system of fertilization may cost more than the 

 product will sell for, and in that case it is simply impracticable. 

 Under such circumstances, the pressure of necessity may drive 

 the skilled and scientific farmer to rely upon skill in plundering 

 the soil of its natural fertility, and of transmitting it to those 

 who come after him, in a ruinous condition. Science and prac- 

 tice cannot be divorced, but we must not despoil the national 

 domain, the natural inheritance of posterity, by divine right 

 theirs. 



The fallow-crop has called forth much discussion as to its 

 true function and place in agriculture. It appears to be now 

 fully established that the legumes, used for such crops, possess 

 the power to produce combined nitrogen, in connection with 

 certain microbes, during their growth. That growing plants 

 arrest the escape of nitric acid from the soil by leaching, is per- 

 fectly clear, for they actively absorb and assimilate it during their 

 growth. This nitric acid of soils is, in small part, of atmospheric 



