RELATIONS OF FEEDING TO FERTILITY. 



35 



Consequently you sec at once tlu; iin[)()S.sihility of carrying on un- 

 limited production without looking to this question of fertility. A 

 system of exhaustion would i)revail if that should be carried on. 

 We find this proved in i)ractice. Undertake year after year to 

 produce crops from your soil without returning these fertilizing 

 materials to it, and the crops refuse to grow because you have car- 

 ried otf the material which was within their reach. It has been sold 

 from the farm by the carrying away of these raw productions. There 

 may be an immediate profit in doing this, and if you have a strong 

 soil, exceedingly rich in fertilizing material, a succession of crops 

 possibly may be grown and removed in a raw state from the farm, 

 but sooner or later with any soil, I care not how rich it may be, the 

 solemn fact will present itself that you have sold the fertility of your 

 farm, and that the privilege of securing paying crops from the soil 

 has been sold with it. 



Here comes in the advantage of feeding. If stock husbandry be 

 introduced upon the farm and these crops are marketed by feeding 

 to the stock, a different result is secured. In feeding these crops to 

 the stock, only a part of the elements of fertility are appropriated 

 in the animal economy ; that is, only a portion of the nitrogen, phos- 

 phoric acid and potash which these animals masticate and digest, is 

 assimilated in the animal economy. Far the larger part of it is 

 passed otf as waste material and is left upon the farm. The amount 

 and kind of material that is assimilated bj' the animal varies con- 

 siderably with what the animal is doing, but far the larger part of it 

 in every case remains upon the farm. 



Plant Food taken from Soil by One Ton. 



