RATIONAL FERTILIZATION. 175 



is secured an intelligent explanation of the results. There is no 

 scarcit}' of valuable testimony to the fact of an exceptionally 

 good success in raising fruits and garden crops b}' the aid of com- 

 pound manurial matters such as barnyard manure, vegetable com- 

 post of various descriptions, wood ashes, and others of a similar 

 more or less ill defined composition ; yet it is equally well under- 

 stood that but little satisfactory explanation can be given in many 

 instances regarding the particular relation which exists between 

 the constituents or conditions of the manurial substances applied 

 and the quality of the crops raised by their aid. 



The world-wide reputation of barnyard manure and wood ashes 

 dates back not merely one or two centuries ; their good effects 

 have been known for thousands of years. Are we prepared to 

 acknowledge that nothing more has been learned during the pres- 

 ent century in regard to the feeding of plants than to use a little 

 more or less of either substance, as circumstances may broadly 

 indicate, to secure success? Most certainly- not ; for we have very 

 good reason to believe that their ancient and general reputation 

 rests on their complex character, and on their beneficial influence 

 over various physical and chemical qualities of the soil. They 

 contain in the majorit}' of cases more or less of all the essential 

 soil constituents which our cultivated farm and garden plants 

 need. They can supply on that account, to some extent at least, 

 not only known but alsc unknown deficiencies of plant food ; and 

 m ay thus secure, other circumstances being favorable, for a 

 longer or shorter period of time a reasonable return when applied 

 in liberal quantity. 



Experience has shown that refuse manurial matter like barnyard 

 manure is most efficient when used for the reproduction of those 

 crops which have contributed materially to its manufacture ; and 

 the same proposition may be maintained with reference to the 

 manurial value of vegetable compost or ashes. 



The exceptional occurrence of these conditions materially limits, 

 in the light of our present information, their claim of being the 

 best of manures for the farm or garden, and needing no farther 

 supplementing to meet any special deficiencies of plant food. The 

 whole aspect of the question how to manure efficiently has grad- 

 ually but decidedly changed within the last fifty years. 



We prefer today to speak of feeding plants. To feed plants 

 intelligentl}' implies possession in a fair degree of two kinds of 



