1192 
Journal of Agricultural Research 
Vol. XXXI, No. 12 
Table I gives the yield in pounds of the wheat and straw. It 
also shows the percentage of nitrogen in the crop and the total 
number of pounds of nitrogen removed by the crop. • The average 
percentage of moisture found in the first 3 feet ot soil during the 
growing season, the average parts per million of nitrate nitrogen, and 
the concentration of the nitrate nitrogen in the soil solution are 
also included. The moisture and nitrate data are based on a 3-foot 
average on the assumption that that found in the soil at greater 
depths has but little influence upon yield or quality of wheat. An 
inspection of part 1 of this table shows a variation in yields which 
can hardly be attributed to a difference in the moisture content of 
the soil, or can it be attributed entirely to a variation in the different 
amounts of available nitrogen present. Table II, giving monthly 
precipitation and mean monthly temperatures, shows a variation 
in both of these factors which must be considered. While both 
moisture and nitrates affect quality and yield, there are other factors, 
such as temperature, sunshine, and length of growing season, which 
must also be considered. Although a comparison can not be made 
of the yield and protein content of the grain and straw in relation 
to the moisture found in the soil for the different years on the con¬ 
tinuously cropped and alternate fallow and cropped plots, yet it is 
but fair to assume that comparisons can be made for the same year 
when climatic conditions are necessarily the same. 
Table II .—Monthly precipitation and monthly mean temperature records for 
Bozeman , Mont., from April , 1911 , to August , 1917 
Year 
Monthly precipitation 
Monthly mean temperature 
April 
May 
June 
July 
Au¬ 
gust 
Total 
April 
May 
June 
July 
Au¬ 
gust 
Inches 
Inches 
Inches 
Inches 
Inches 
Inches 
o p 
° F. 
o p 
o p 
o p 
1911__ 
1.57 
3.56 
3.06 
0.84 
1.52 
10.55 
38.5 
47.4 
58.7 
60.8 
58.’3 
1912_ 
3.59 
2.66 
2.69 
1.91 
1.63 
12.48 
31.3 
49 .2 
58.7 
59.9 
58.4 
1913__ 
1.65 
2.54 
3.19 
2.17 
1.80 
11.33 
42.6 
49.0 
58.1 
60.1 
643 
1914_ 
2.02 
2.05 
3.54 
1.28 
. 11 
9.00 
40.6 
50.6 
55.4 
65.1 
61.8 
1915.... 
2.60 
3.67 
4.44 
3.91 
.38 
15.00 
48.6 
46.8 
51.4 
57.3 
642 
1916_ 
2.10 
2.99 
2.33 
1.58 
1.38 
10.38 
40.8 
43.0 
53.1 
64.2 
60.9 
1917.-. 
1.72 
2.37 
2.46 
.36 
.53 
7.44 
35.4 
46.9 
55.1 
68.8 
63.4 
Average.-_- 
2.17 
2.83 
3.10 
1. 72 
1.05 
10.88 
41.1 
47.5 
55.8 
62.3 
61.6 
Normal °_ 
1.93 
2.82 
2.88 
1. 32 
.93 
9.88 
41.3 
49.4 
57.2 
63.7 
62.9 
« 35-year average. 
RESULTS FROM WINTER WHEAT 
By referring to Table I it will be seen that the average yield of 
winter wheat grown on the continuously cropped plots was 72.9 
pounds; the average yield of winter wheat on the alternate fallow 
and crop plots was 120.5 pounds. The average moisture content on 
the continuously cropped plots, to a depth oi 3 feet, was 17.00 per 
cent; the moisture content on the alternate fallow and crop was 17.57 
per cent. The average nitrogen content of the grain grown on the 
continuously cropped plots for the seven years was 2.09 per cent; 
that grown on the alternate fallow and crop plots was 2.48 per cent, 
a decided increase over the continuously cropped plots which had a 
lower percentage of moisture in the soil. 
