HOW DISCORDANCES IN RESULTS ARISE. 47 



research has afterwards shown to be utterly void of foundation. 

 Thus, by incorrect experiments instead of being promoted, as 

 by such trials it ought to be agriculture, both as a science and 

 an art, is materially restrained, and the attainment of truth 

 hindered and delayed. 



6. Why the results of analogous field experiments are often 

 so discordant. 



That the results of analogous field experiments have often 

 been so discordant the effects of the same manure, for example, 

 in different fields or localities, found to be so very different has 

 to some been a cause of much discouragement, while to others 

 it has served as an argument against the utility of experiment- 

 ing altogether. The reader of the preceding sections will easily 

 see how such discordances must have been almost unavoidable, 

 as experiments have hitherto been conducted. They may 

 have arisen from the action of one or more of the following 

 causes : 



1. Because true averages of the natural productiveness of 

 the field, or the limits of natural variation in the crop, have not 

 in each case been determined ; and thus the true effects or differ- 

 ences in the amount of crop, caused by a given application, 

 cannot have been ascertained. 



2. Because the original nature of the soils their physical 

 character, that is, and their chemical composition may have 

 been different in the several experiments. 



3. Because the previous cropping or manuring, or generally 

 the agricultural history of the pieces of land, may have been 

 different thus establishing very influential artificial differences 

 between soils originally alike. 



4. Because the quality of the substance, the period of apply- 

 ing it, the manner and form in which it is applied, the state of 

 the weather at the time, or the state of the crop when the 

 applications were made, or that of the season afterwards, may 

 not have been in each case equally favourable. 



5. Because a difference in the variety of the same crop 

 grown in two places, or in the time of gathering or lifting it, 

 may have affected the results. 



