Sept. 9,1918 Deep Tilling and Dynamiting in the Great Plains 
491 
Production from all methods was heavy in both years. The mean ratio 
of all crops is 100, with a probable error of 1.6. With all crops except 
flax the average result is slightly against subsoiling, but by a margin less 
than the calculated probable error. Flax from an unduplicated pair of 
plots shows an apparent increase from subsoiling, but as this result with 
this crop in comparison with others is exactly contrary to those obtained 
at Huntley it must be concluded that the departures in each case are 
due to the experimental error. If this conclusion is correct, subsoiling 
has been without significant effect at this station. 
BELLEFOURCHE FIELD STATION 
The Bellefourche Field Station, near Newell, S. Dak., is located on a 
heavy clay soil derived from the decomposition of Pierre shale. From 
the soil at the surface there is a rapid change to broken but undecom¬ 
posed shale. Near the bottom of the second foot there is a comparatively 
impervious layer of soil. 
Table IV. —Yields at the Bellefourche ( 5 . Dak.) Field Station of spring wheat, winter 
wheat, oats, corn, and barley each year from 1909 to 1916, inclusive, on plot E, subsoiled, 
and plot B, not subsoiled but otherwise similarly treated , together with the average of 
each method for the entire period of years; the ratio of the yield on E to the mean of the 
yield on B and E each year; the mean ratio; and the probable error of the mean ratio 
[Yields of all crops in bushels per acre] 
Yield or ratio. 
Crop and plot. 
1909 
19x0 
191X 
19x2 
1913 
1914 
19x5 
19x6 
Aver¬ 
age. 
Proba¬ 
ble 
error of 
mean 
ratio. 
Spring wheat: 
4.8 
4 * 7 
10. 8 
Plot B. 
23-3 
28.5 
O. 0 
0.0 
0. 0 
7*9 
6.8 
57 - 7 
55-6 
13 * I 
14. O 
Plot E. 
O. O 
0. 0 
0. 0 
16. 6 
Ratio of E 
to mean.. 
99 
± 3-8 
IIO 
93 
98 
121 
104 
Winter wheat: 
Plot B. 
34-4 
29-3 
O. O 
0. 0 
0. 0 
21. 8 
13*4 
14. 7 
20. 4 
25. 2 
8. 8 
12.4 
12. I 
Plot E. 
O. O 
0. 0 
0. 0 
18. 7 
8-5 
Ratio of E 
to mean.. 
± 2. 9 
92 
92 
105 
III 
98 
100 
Oats: 
Plot B. 
46. 9 
60.8 
O. 0 
0. 0 
6. 6 
15.8 
16. 3 
24. 7 
20. 3 
119. 7 
118.1 
23. I 
21. I 
29. 6 
3 °* 5 
Plot E. 
O. 0 
0. 0 
7*3 
Ratio of E 
to mean.. 
± 2.3 
113 
105 
102 
90 
99 
95 
101 
Barley: 
8- 9 
18. 0 
Plot B. 
2 K.O 
33-8 
4. 8 
0. 0 
0. 0 
0. 0 
7 . I 
7 i- 5 
78.9 
33-6 
29. 2 
Plot E. 
0. 0 
a 0 
7.8 
&3 
i 9 - 5 
Ratio of E 
to mean.. 
d=io. 6 
US 
0. 0 
93 
94 
93 
83 
Com: 
Plot B. 
Plot E. 
23 - S 
20. 8 
0. 0 
0. 0 
0. 0 
0. 0 
29.7 
26. 3 
<5. 5 
9*4 
0. 0 
0. 0 
53 *o 
47*7 
31. 2 
32.3 
l8. O 
iy . 1 
Ratio of E 
to mean.. 
db 3 . 2 
94 
94 
n8 
95 
102 
101 
