Experimental Error in Crop Tests 15 
Fig. 1 — Illustrating principle of competition between adjacent rows. 
Winter wheat on right; spring wheat on left. Due to competition 
with the winter wheat, the first row of spring wheat grew only 
four inches tall with no grain production. The second row was 
nearly normal and the third row entirely normal. 
to eliminate the accidental mechanical and physical errors 
due to variation in soil, exposure, stand, etc. These nursery 
rows were spaced 10 inches apart. The relative yields in 
either the entire five-row block or the three inner rows, as 
indicated, were regarded as the correct relative yields for 
the season. A difference in the relative yields when tested 
in alternating rows, as compared with the relative yields in 
blocks, is chiefly due to, and measures, the competition be- 
tween the crops compared in rows. In part of the tests the 
blocks were harvested as individual rows, which permitted a 
study of the effect of plat competition upon the border rows 
of five-row plats. The straw yields as well as the grain yields 
were also secured in a portion of the tests. 
ROW COMPETITIOX IX RATE-OF-PLANTING TESTS WITH 
WHEAT AND OATS 
During the years 1913 and 1914, both oats and winter 
wheat were grown at two distinct rates of planting in both 
