Sept. 9,1918 Deep Tilling and Dynamiting in the Great Plains 
493 
Table V .—Yields at the Ardmore (S. Dak.) Field Station of spring wheat, winter wheat , 
oats, barley, and corn each year from 1913 to iqi6, 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. 
1913 
1914 
1915 
1916 
Average. 
Probable 
error of 
mean 
ratio. 
Spring wheat: 
Plot B . 
O. O 
(a) 
49*5 
43*3 
Q -3 
17*5 
12. 8 
22.3 
18.7 
89 
Plot E . 
0. 0 
(a) 
Ratio of E to mean. 
84 
± 3 * 8 
y 0 
Winter wheat: 
Plot B. . ... 
0. 0 
(a) 
20. 2 
29^8 
19.7 
22. 6 
107 
Plot E. 
0. 0 
w 
y * 
33*3 
107 
34-5 
IQ 7 
Ratio of E to mean. 
4 - 0 
Oats: 
Plot B . 
0.0 
(a) 
75*4 
59*4 
88 
42. 2 
25. O 
74 
in 0 
Plot E . 
0. 0 
(° 
0 y* z 
28 1 
Ratio of E to mean . 
81 
± 5*9 
. 
_ 
Barley: 
Plot B .. 
0. 0 
(a) 
54 *o 
5i* 0 
07 
25. 2 
2 A. 7 
26. 4 
25. 2 
98 
Plot E . 
- 0. 0 
a 
Ratio of E to mean . 
\ / 
OO 
io. 8 
7/ 
yy 
Com: 
Plot B . 
0. 0 
O. O 
43 * 7 
3 2 * 9 
86 
28. 7 
26. 6 
18.1 
IA n 
Plot E. 
0. 0 
0. 0 
Ratio of E to mean. 
96 
■ lj t* y 
nT 
± 4 * 2 
y A 
a Crop destroyed by hail. 
SCOTTSBLUFF FIEXD STATION 
The soil of the Scottsbluff (Nebr.) Field Station is a comparatively 
light sandy loam. At a depth varying from 5 to 8 feet there is a sharp 
break from this soil to either sand or Brule clay. Above this point the 
soil offers no unusual resistance either to the downward passage of 
water or to the development of roots. 
Table VI presents five years' results with spring wheat, oats, barley, 
and corn at this station. Considered either by crops or by years, the 
only consistency to be noted is the heavier production on the subsoil 
plots in 1912. In the average of the five years the differences exhibited 
are very small and are less than the probable error with all crops except 
barley, where the difference only slightly exceeds the probable error. 
