July i, 1920 



Universality of Field Heterogeneity 



heterogeneity was overemphasized as a factor influencing plot tests. 

 This question can be answered only by actually determining the degree 

 of heterogeneity existing in the fields which have passed the criticism of 

 agricultural experts. 



It will be conducive to brevity to have a definite system by which the 

 arrangement of the plots in a field may be described. We shall consider 

 the plots arranged as soldiers in ranks and files. The worker inspects 

 the plot records of a field as recorded on a map or table. By ranks we 

 understand the horizontal rows of plots, by files the vertical rows. 



FIG. i. Montgomery s diagram of 5.5 by 5.5 foot plots of Turkey wheat, showing variations in the per 

 centage of nitrogen in the grain. 



Thus figure i, showing the nitrogen content of wheat plots 5.5 by 5.5 

 feet given by Montgomery (17), may be considered made up of 16 ranks 

 and 14 files. 



In considering rearrangements or combinations of plots we shall 

 refer to the ranks and then to the files an order easily carried in mind 

 by remembering the trite expression &quot;rank and file.&quot; Thus in referring 

 to a 2 by 5 fold combination we mean that two adjacent ranks and five 

 adjacent files of plots were combined. Individual plots may be easily 

 designated. Thus, the plot belonging to the sixth rank * and the fifth 

 file in the nitrogen contents of wheat yields contained 1.93 per cent 

 nitrogen. 



J Ranks are numbered from the top of map, files from the left. 



