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MISSOURI AGR. EXP. STA. RESEARCH BULLETIN 49 



Again the single rows are distinctly more variable than the 3-row 

 plot, in this case to the extent of 10 per cent. The 5-row and the 

 3-row plots are about equally variable, the slight advantage in this case 

 being in favor of the latter. 



To summarize, it is evident that the protected 3-row plot is some- 

 what less subject to plot variability than the protected single-row, but 

 the relative value of the 5-row plot harvested entire and the same plot 

 harvested as a protected 3-row block is not clear. Some further 

 comparison of these two methods was made in 1921. The variability 

 of the check plots in both the wheat and oats tests was computed as 

 protected 3-row and as unprotected 5-row plots. In the wheat tests 

 the check variety was Poole, seeded at 5 pecks per acre in every 

 seventh plot in the variety test, and in every sixth plot in the mixture 

 test. In the oats tests the check variety was Kherson, seeded at 10 

 pecks per acre in every sixth plot. The results are shown in Table 23. 



23. YIELD AND VARIABILITY OF CHECK PLOTS. 

 Three-row and Five-row. Wheat and Oats Tests, 1921. 



In no case are the differences very great. The variability of 3-row 

 blocks is slightly greater in the mixture test and that of 5-row blocks 

 in the variety test of wheat. There is practically no difference between 

 the two in the oats tests. 



Apparently there is no constant material gain in plot uniformity 

 obtained by the inclusion of the border rows of the 5-row plot, even 

 though the size of the plot is materially increased by this procedure. 

 Even if variability were decreased by their inclusion, the practice would 

 be of doubtful value in most tests, for the reasons given in the last 

 section ; but with practically no decrease in variability there is left no 



