COMMERCIAL FERTILIZERS IN HORTICULTURE. 15l> 



Two facts handicap a discussion of certain special questions 

 that relate to this subject as viewed from the standpoint of the 

 horticulturist. 



First. There is a dearth of exact knowledge that can be uni- 

 versally applied to the use of commercial fertilizers. We have 

 many theories, opinions, and think so's, but altogether too few 

 demonstrations. 



Second. There is a perplexing complexity and variation of 

 conditions under which different men ai'e working. 



When I first began to cast about in my mind for the lines of 

 thought which I would discuss hei'e today, these two topics at 

 once presented themselves : 



First. Fertilizers that we may safely regard as " specifics " for 

 particular crops. 



Second. The composition of fertilizers in its relation to the 

 quality of the product. 



These two topics are today in the forefront of active thought 

 pertaining to plant nutrition, and it would give me great pleasure 

 at this time to incorporate into a creed of practice well demon- 

 strated facts bearing upon these important considerations. 

 When, however, I came to turn over the records of experimental 

 work upon the relation of different compounds and mixtures of 

 compounds to the development and quality of vegetables and 

 fruits, I found such an absence of data, such conflicting testi- 

 mony, and, in general, such an unsatisfactory condition of 

 statement, that a decision was at once reached that I would not 

 come here and talk about hypotheses or half -demonstrated 

 theories. There are, however, certain general remarks that with 

 your indulgence 1 will make in this connection. 



In the first place, I am somewhat skeptical in the matter of 

 "specifics" in plant nutrition, at least so far as quantity of 

 l)roduct is concerned. It is true that the needs of all plants for 

 food are not just the same, because both the relative and absolute 

 quantities of ingredients that they take up differ, and because 

 some plants thrive with a food supply to which others are more or 

 less indifferent. If by "specific" manuring we mean the 

 supplying of a particular plant with its needed food elements in 

 acceptable forms, so that it will make rapid and generous growth, 

 I have no exception to take to the term, but I hold that the 

 ^'■needed food elements'' and the ^'-acceptable forms" are too 



