54 



BREEDING CROP PLANTS 



for the purpose of correcting yields where there is a tendency 

 to vary in one direction across a field. 



TABLE IX. DIRECT CORRECTION FOR YIELD WHERE VARIATION is IN ONE 

 DIRECTION ACROSS A FIELD 



In the second column of Table IX the actual yields are given 

 of 25 contiguous J^g-acre plots across a field. The figures show 

 a more or less gradual decrease, reading from top to bottom. 



There is a difference of 500 Ib. between the average yield of 

 the first five plots and the average yield of the last five plots, or an 

 average difference from plot to plot of 25 Ib. This correction 

 is applied by adding to those on one side and subtracting from 

 those on the other side of the centrally located plot. The amount 

 added or substracted depends on the distance from the center, 



