EXPERIMENTS IN FIELD PLOT TECHNIC 



45 



carded, since they are made up of rows protected from varietal compe- 

 tition by border rows. In each of the computations summarized be- 

 low each check plot is represented by only one yield. For example, in 

 determining the yield and standard deviation of single rows in the 20 

 check plots of the oats variety test of 1919, the constants for single 

 rows are the average of determinations made independently for Row 

 2 of each of the 20 plots, for Row 3, and for Row 4. The determina- 

 tions for 3-row plots are similarly made from the computed yields of 

 the three interior rows of each check plot, and those for 5-row plots 

 from the computed yields of the entire plots. Thus each determination 

 represents the same number of plots and the same area, the only dif- 

 ference being in the size of the individual plot. It would be possible, 

 of course, to test 40 per cent more varieties with the same number of 

 replications or to increase the number of replications by 40 per cent 

 for the same number of varieties on the same area, if 3-row blocks 

 were used rather than 5-row blocks. 



The yield and variability of check plots of different sizes in the 

 barley variety test of 1919 are shown in Table 19. The variety grown 

 in these check plots was Oderbrucker, seeded at the rate of 8 pecks 

 per acre. The check variety was grown in every sixth plot. 



TABLE 19. YIELD AND VARIABILITY OF CHECK PLOTS. 

 Single-row, Three-row, and Five-row Barley Variety Test 1919. 



The variability of the single-row plots is 12 per cent higher on 

 the average than that of the 3-row plots. That is, 3-row plots with 



