CEREAL INVESTIGATIONS AT THE NEPHI SUBSTATION. 13 



a=yield of nearest check plat. 

 b=average yield of all check plats. 

 x=actual yield of nearest variety. 

 y=computed yield of nearest variety. 

 y=x+(b-a). 



In 1908, 7 check plats of Koffoid wheat (C. I. No. 2997) were used. 

 This number was found to be too few, because they had to be scattered 

 so widely that they did not represent the true value of soil variations. 

 This was the case also in 1909, when 8 checks of the same variety 

 were used. In 1910, 23 checks of Turkey wheat (C. I. No. 2998) 

 were used and more accurate computations were made. Seldom 

 were there more than 7 varietal plats between any 2 checks. In 

 1911 and 1912 about the same number of checks was used as in 1910. 



The check-plat system described above did not prove as satisfactory 

 as was hoped. It afforded a means of gaining a better idea of the 

 relative yielding power of the several varieties than would be possible 

 without the use of any system designed for that purpose. But the 

 checking system used at Nephi was lacking in accuracy. The yields 

 of the various check plats were influenced by so many uncontrollable 

 factors (soil variation, winterkilling, weeds, etc.) that to assume that 

 any one of the other varieties would be affected to a like degree would 

 be more a theory than a determination. Though the check yields 

 were fairly uniform in many instances, occasionally there would be a 

 variation as great as 100 per cent. More than this, the variety 

 growing on a plat next to a low- yielding check plat sometimes would 

 yield very high. In the latter case the computed yield of the variety 

 would necessarily fall far below its actual yield. In other cases the 

 reverse condition would exist and the computed yield- of the variety 

 .would greatly exceed its actual yield. Such instances show the inac- 

 curacy of the checking system used. 



It is believed that a replication of plats devoted to a test of any 

 one variety would be far more dependable as a means of showing 

 the relative yielding power of that variety than would the check- 

 plat system. Where a replication of plats is practiced, the number 

 of varieties tested might necessarily be reduced. Then, too, more 

 work in connection with the varietal test would be necessitated, but 

 the accuracy of the results obtained would compensate for the extra 

 labor involved. 



The computed yields of the winter varieties grown at Nephi during 

 the years 1908 to 1911, inclusive, are reported in connection with 

 the absolute yields, but only for the purpose of comparison. 



Collection of Data. 



Throughout the entire season the behavior of the crops on the plats 

 in the varietal test was observed closely. In the spring, after it was 

 reasonably certain that no more plants would appear, the number 



