No. 4.] SOIL FERTILITY. 135 



bulletin in question to be. But avo should endeavor to hold 

 ourselves in an impartial attitude of mind, and not alloAv the 

 real lessons of this discussion to be missed. 



The public is certainly justified in gaining the impression 

 from readino; this bulletin that there are few soils which will 

 not sustain satisfactor}^ crop production indefinitely, pro- 

 vided proper physical conditions exist, and a suflicient water 

 supply is available. In support of this statement, I quote 

 from the bulletin in question : " Apparently, therefore, all 

 these soils are amply supplied with the necessary mineral 

 plant foods, and these plant foods are not in themselves a 

 matter of such paramount importance to the agriculturist, 

 for their supply as regards the plant is determined by the 

 suppl}^ of soil moisture which the crop can obtain from the 

 soil." " It appears, further, that practically all soils contain 

 sufficient plant food for good crop yield, that this supply will 

 be indefinitely maintained, and that the actual yield of plants 

 adapted to the soil depends mainly, under favorable climatic 

 conditions, upon the cultural methods and suitable crop rota- 

 tion." It is natural that when the practitioner's attention 

 has been called to these statements he should at once ask 

 whether the teachers of agricultural science have been wrong 

 in urging as conditions of first importance the careful pres- 

 ervation of farm manures and the judicious use of commer- 

 cial fertilizers ; whether, if the soil had been properly 

 managed, its fertility would not have been maintained 

 without any attempt to reinforce certain of its constituents. 



It is important, therefore, for us to inquire, and I think 

 Ave may do this Avithout entering into unfair or unkind criti- 

 cism, Avhether the status of scientific knoAvledge and the data 

 which are presented in Bulletin No. 22 justify any important 

 readjustment of existing thought touching the maintenance 

 of soil fertility. The authors of the bulletin reach their 

 conclusions partly through the consideration of pre-existing 

 knowledge or theory, and partly from data Avhich are the 

 result of their OAvn investigations, I have tried to give this 

 bulletin careful and impartial study, and I am unable to see 

 Avhy the folloAA^ng is not a fair analysis of the reasoning 

 which tlie authors adopt. If I may use the terms of formal 



