6 
BULLETIX 1039, U. S. DEPARTMENT OF AGRICULTURE. 
proximately the growing period for the cereals on dry land at Xewell. 
The seasonal precipitation was a prominent factor affecting the yields 
of grain. The monthly, seasonal, and annual precipitation recorded 
in inches at the Belle Fourche Farm from 1908 to 1919, inclusive, is 
shown in Table I. The seasonal and annual precipitation is also 
shown graphically in figure 2. 
Table I. — Monthly, seasonal, and annual precipitation at tltc Belle Fourche 
Experiment Farm, 1908 to 1919. inclusive. 
[Depth, of precipitation in inches. T=trace.] 
Year. 
Jan. 
Feb. 
Mar. 
Apr. 
May. 
June, 
July. J Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
March 
to 
July, Total, 
inclu- 
sive. 
1908 
1909 
1910 
1911 
1912 
1913 
1914..... 
a0.20 
a. 17 
.73 
.13 
.24 
.57 
T 
.92 
.36 
a0.19 
a. 23 
.70 
.05 
.10 
.24 
1.00 
1.01 
.23 
.74 
.64 
.57 
al.65 
a. 19 
.93 
.09 
.71 
.99 
.29 
.16 
.98 
.27 
.81 
.87 
1.16 
.84 
1.57 
.17 
2.32 
.25 
1.09 
2.58 
.64 
2.51 
2.40 
2.14 
3.95 
3.87 
1.26 
.45 
2.26 
1.98 
2.22 
2.32 
3.17 
3.71 
1.60 
1.14 
1.47 
5.59 
1.51 
.50 
.29 
3.10 
2.09 
4.74 
2.19 
.97 
1.17 
.35 
1.26 
2.45 
1.42 
.80 
3.20 
.35 
1.34 
0.62 
. 55 
1.03 
1.86 
2.80 
.26 
1.12 
0. 52 
1.07 
2.92 
.92 
3.49 
2.38 
.35 
1.26 
.20 
.35 
3. OS 
1.20 
a2.10 
.76 
.27 
.39 
.51 
1.86 
1.77 
1.25 
.99 
.46 
.22 
2.49 
a0.20 
.73 
.11 
.98 
.04 
.10 

.43 
.33 
T 
.15 
1.22 
aO.91 
1.28 
.10 
.30 
.13 
.45 
.43 
.17 
.28 
.92 
.85 
.62 
9.49 
12.94 
6.69 
2.01 
8.78 
6.67 
7.03 
15.54 
8.99 
8.26 
9.39 
7.09 
14. 23 
17. 73 
12. 55 
6.64 
16.09 
12.53 
11.70 
1915 
1916 
5. 74 | . 44 
2.01 2.02 
.80 I 1.67 
3. 41 2. 99 
2. 59 1. 02 
21.02 
13.40 
1917 
1918 
1919 
Average — 
.92 
.99 
.04 
13. 32 
18.31 
14.25 
.44 
.48 
.66 
1. 47 I 2. 33 
2.00 
2. 11 1. 37 
1.48 
1.09 
.36 
.54 
8.57 
14.31 
a From records of the United States Weather Bureau at Vale and Orman, S: Dak. 
RELATION OF PRECIPITATION" TO YIELDS OF GRAIN. 
The limiting factor in crop production at Xewell usually has been 
the moisture supply. Winter grains have been subject to cold in- 
jury, so that the yields may depend on several factors. The yields 
of spring grains, however, are closely associated with the amount 
and distribution of the rainfall. The precipitation during the grow- 
ing period is the most important. The amounts and distribution of 
this seasonal precipitation have largely determined the yields of 
spring grain on the dry land at Newell. In some seasons, as that of 
1912, the rains came too late to benefit the early varieties of grain. 
In 1910, 1917, and 1919 the lack of moisture during the heading and 
ripening period caused low yields. 
A rain of less than 0.3 inch during the growing season, unless 
followed or preceded by other rains within 24 hours is of almost no 
value to grain crops in this section. The moisture from light rains 
does not penetrate far into the soil and is soon evaporated. In 1911 
there was a total precipitation of 2.01 inches during the growing 
season, March to July, inclusive, but this came in such small and 
scattered showers that it was useless for crop production. Conse- 
quently all grains were a failure that year. 
