CROP ROTATION AND CULTURAL METHODS AT AKRON, COLO. 13 
spring wheat was less than 7 bushels per acre. Spring wheat seldom 
succeeds when winter wheat fails. It is not as reliable as winter 
wheat over a term of years and does not respond as well to good 
cultural treatment or to favorable seasons. Spring wheat produced 
more than the average winter- wheat yield of 12.8 bushels per acre 
only six times during the 15-year period, and it exceeded its own 
average yield of 10.3 bushels the same number of times. The 
highest average yield of spring wheat per acre was 27.3 bushels, in 
1915. The lowest yield was in 1918, wnen most methods failed and 
the best averaged only 3.9 bushels. Table 6 shows the annual and 
the 15-year average yields of spring wheat under 13 different methods 
of soil treatment. The 15-year average yields are shown graphically 
in Figure 6. 
The highest average yield for the 15 years was 13.2 bushels, on 
fallow. The plat alternately cropped and fallowed averaged 12.5 
bushels, and the plat on fallow in the 3-year rotation (No. 5) aver- 
aged 14.8 bushels per acre. The next highest yielding preparations 
were spring-plowed corn ground, 12.6 bushels; fall-plowed corn 
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Fig. 6.— Average yields of spring wheat obtained under different tillage methods at the Akron 
Field Station for the 15 years from 1909 to 1923, inclusive 
ground, 11.5 bushels; and spring plowing on land continuously 
cropped to wheat, 11.5 bushels. The average yield of four plats on 
disked corn ground was only 9.6 bushels per acre. One of these was 
in a 3-year rotation and averaged 14 bushels per acre; one was in 
a 4-year rotation of sweet clover for green manure, oats, corn, and 
wheat, and averaged 10.5 bushels; one was in a 6-year rotation of 
bromegrass three years, oats, corn, and wheat, and averaged 6.5 
bushels ; and one was in a similar sod rotation containing three years 
of alfalfa and averaged 7.6 bushels. The difference between the 
yield in the 3-year rotation and the yields in the other rotations was 
due in part to soil differences due to different locations in the field 
and in part to the influence of other crops in the rotations. The 
evidence indicates that the yield of 14 bushels per acre in the 3-year 
rotation is the one most nearly comparable with the yields incident 
to other methods already mentioned. If this is true, disked corn 
ground is equal to fallow as a preparation for spring wheat, is superior 
to corn ground plowed either in the fall or in the spring, and superior 
to ground that raised a crop of small grain the preceding year. 
