CHOP ROTATION IN RELATION TO SOIL PRODUCTIVITY 
35 
Table 33. — Yields of corn, oats, and wheat, and gains per acre, on plot 20 {manured) 
in rotation for 25 years, 189^-1918, Wooster, Ohio 
Years 
Yields and gains per 
acre (bushels) 
Corn 
Oats 
Wheat 
Plot 
20 ma- 
nured 
; Plot 
20 if 
unma- 
nured 
Gain 
due to 
manure 
Plot 
20 ma- 
nured » 
Plot 
20 if 
unma- 
nured 
Gain 
due to 
manure 
Plot 
20 ma- 
nured 
Plot 
20 if 
unma- 
nured 
Gain 
due to 
manure 
1894. 
1895. 
1S96. 
1897. 
1898 
17.28 
37.21 
55.68 
44.54 
39.86 
19.87 
35.29 
50.84 
24.74 
28.31 
-2.59 
1.92 
4.84 
19.80 
11.55 
23.98 
34.22 
26.56 
37.50 
39.68 
24.27 
• 27.60 
24 11 
36.97 
36.09 
-0.29 
6.62 
2.45 
0.53 
3.59 
17.46 
7.17 
4.79 
12.92 
15.04 
17.99 
2.61 
1.22 
8.67 
10.65 
-0.53 
4.56 
3.57 
4.25 
4.39 
5-year average 
38.91 
31.81 
7.10 
32.39 
29.81 
2.58 
11.48 
8.23 
3.25 
5-year average 
1899. 
1900. 
1901. 
1902. 
1903. 
41.32 
37.96 
49.07 
74.82 
12.21 
25.52 
26.87 
38.65 
56.41 
3.82 
15.80 
11.09 
10.42 
18.41 
8.39 
44.06 
34.22 
38.66 
31.41 
33.91 
34.69 
19.53 
31.56 
29.73 
21.48 
9.37 
14.69 
7.10 
1.68 
12.43 
13.50 
7.75 
14.33 
16.42 
21.33 
7.75 
0.69 
6.36 
10.28 
16.20 
5.75 
7.06 
7.97 
6.14 
5.13 
43.08 
30.26 
12.82 
36.45 
27.40 
9.05 
14.67 
8.26 
6.41 
1904. 
1905. 
1906. 
1907. 
1908. 
37.25 
50.57 
53.54 
67.92 
42.25 
18.96 
35.38 
36.04 
39.74 
27.67 
18.29 
15.19 
17.50 
28.18 
14.58 
54. 06 I 46. 61 
47.65 ] 38.98 
37.50 1 28.25 
22. 19 j 14. 84 
48.59 | 41.82 
7.45 
8.67 
9.25 
7.35 
6.77 
22.21 
13.12 
37.08 
22.50 
27.46 
10.00 
5.41 
22.72 
13.96 
17.68 
12.21 
7.71 
14.36 
8.54 
9.78 
5-year average 
50.31 
31.56 
18.75 
42. 00 i 34. 10 
7.90 
24.47 
13.95 
10.52 
5-year average 
5-year average, 1914- 
1918 3 
1909. 
1910. 
1911. 
1912. 
1913. 
43.11 
20.35 
61.89 
( 2 ) 
31.50 
23.44 
6.14 
35.15 
( 2 ) 
13.52 
19.67 
14.21 
26.74 
( 2 ) 
17.98 
45.39 j 34.87 
46.09 [ 38.59 
32.73 . 16.51 
40.07 ; 31.47 
17. 42 13. 30 
10.52 
7.50 
16.22 
8.60 
4.12 
33.21 
23.54 
20.33 
6.33 
26.54 
22.41 
7.76 
7.42 
1.17 
16.87 
10.80 
15.78 
12.91 
5.16 
9.67 
39.21 
19.56 
19.65 
36.34 26.95 
9.39 
21.99 
11.12 
10.87 
42.52 
24.89 
17.63 
50. 42 ! 40. 66 
9.76 
25.83 
14.84 
10.99 
25-year average 
42.81 
27.62 
15.19 
39.52 ] 31.78 
7.74 
19.69 
11.28 
8.41 
1 Residual effect of manure applied to corn. 
2 Injury by white grub. 
3 Annual yields not published. 
No direct manure application made on oats in rotation. 
The oat crop on plot 20 in rotation does not receive any direct 
application of manure, but it receives the residual effect of the 4 tons 
of manure applied to the preceding corn crop. In continuous culture, 
the nearest approach to yields comparable with the oat yields on 
plot 20 in rotation are those obtained on plot 5, which receives an 
annual application of 2.5 tons of manure per acre. This explains 
why the oat yields in rotation are compared with those on plot 5 in 
continuous culture, instead of with the average of the yields obtained 
on plots 5 and 6, as in case of the wheat and corn. 
RESULTS WHEN ROTATION AND FERTILIZATION ARE PRACTICED INDEPENDENTLY 
From the 25-year averages given in Tables 30, 31, 32, and 33, 
Table 34 is constructed, summarizing the average yields per acre 
and the increases over check plots in continuous culture, and showing 
the relative values of crop rotation in increasing crop yields when 
rotation and the use of fertilizers are practiced independently of each 
other. 
