210 BOARD OF AGRICULTURE. 



Because we do not know what the physiological functions 

 af the different forms of plant food are, it does not follow 

 that these different functions do not exist ; and if they do 

 exist, why they should not be considered in the cultivation 

 of crops. That different forms of plant food have different 

 functions there is no doubt, and the work of the future is 

 to discover these functions, and to make combinations that 

 shall be adapted to the crops we are growing. Agricultural 

 chemistry began with the discovery of the elements essential 

 to plant growth ; it will not be complete until it has dis- 

 covered the various functions of these ingredients, and 

 adspted them to the wants of man. 



We hear a great deal now-a-days about " complete fertiliz- 

 ers," — as though a " complete" fertilizer was a "sine qua 

 non." Ammonia, phosphoric acid and potash form a " com- 

 plete " fertilizer in the popular acceptance of the terms, but 

 not necessarily a perfect fertilizer. If it contains but one 

 per cent, of ammonia, one of phospht)ric acid and one of 

 potash, it is a " complete" fertilizer; and if it contains ten 

 per cent, of each it is still " complete." It may contain one 

 or all three of these forms of plant food in insoluble forms, 

 and still be "complete ' in the popular sense. A "com- 

 plete " fertilizer is a kind of raanurial blunderbuss loaded 

 with several kiuds of shot, and expected to bring down all 

 kinds of game, or rather to send up all kinds of crops in 

 abundance and perfection. Now, a "complete" fertilizer 

 can be made — in fact, is made — that seems to work well on 

 most crops. A high grade superphosphate with ammonia 

 and potash is an excellent fertilizer, and when used in con- 

 nection with stable manure, or on a rich, unexhausted soil, 

 is probably a good combination for general farm purposes ; 

 but to contend that fertilizers begin and end with a manure 

 that is simply " complete " is to assume that there is nothing 

 more to be learned in this field. Superphosphate of lime 

 was the starting point ; then followed the addition of ammo- 

 nia and finally that of potash, and we had the so-called 

 " complete" fertilizer, still valuable, but by no means per- 

 fect. After that came formulas based upon the analyses 

 of crops, — a great step in the right direction, the promul- 

 gation of which quickened agricultural thought and opened 



