Section III., 1914 [1671 Trans. R.S.C. 



A Systematic Scheme for Experimental Work with Fertilizers. 



By A. T. Stuart, B.A. 



Presented by Dr. Frank T. Shutt, F.R.S.C. 



I. THE IMPORTANCE OF THE STUDY OF FERTILIZERS. 



There are perhaps few problems in agriculture which have aroused 

 so much discussion and upon which are held such conflicting opinions 

 as the fertilizer question. The reason for this is probably to be found 

 in the great number of variables to be encountered — soil, temperature, 

 light, heat, water supply, evaporation, drainage, aeration, fertilizers 

 used, farm crops, rotations, etc. The consensus of opinion at the 

 present time appears to be that few general recommendations can be 

 made but that each and every case must be studied separately. 



This is rather an unfortunate conclusion for the individual 

 farmer. In the first place, he is, of necessity, ill equipped to study a 

 question which has aroused so much discussion even among experts 

 and, secondly, he cannot apportion more time to this than to' other 

 duties. The least which might be offered him is a workable plan for the 

 prosecution of his enquiries. 



In spite of all this every one now admits the benefits to be attrib- 

 uted to a judicious use of fertilizer. The mere fact that the farmers of 

 the world now spend some hundreds of millions of dollars annually for 

 fertilizer is sufficient indication of their value. A "fertilizer experi- 

 ment" is but a means devised to measure or compare values. We, 

 therefore, admit, in fact, are forcibly impressed, by the importance 

 of these values and yet have no very satisfactory measure to translate 

 the same into terms of dollars. 



II. CONSIDERATIONS CONCERNING PLANS OF EXPERIMENTS. 



It is evident that almost innumerable variables, as suggested 

 above, are involved in the "equation." The solution of the problem 

 under perfect and ideal conditions would demand the complete elimina- 

 tion of all variables other than the one under investigation, which 

 in the case of fertilizer experiments is the quantity or variety of fer- 

 tilizer material. Obviously this is impossible; but it is the purpose of 

 this paper to consider the matter, first, from the purely theoretical 

 point of view and, later, to find just how far it can be applied in practice. 



