478 
Journal of Agricultural Research 
Vol. XIV, No. xt 
FREQUENCY OF DROUTHS AS AN INDEX OF THE SEVERITY OF SEASONS 
The frequency of drouths as defined above is not an index of the 
severity of different seasons. In the so-year period, 1895-1914, fifteen 
occurred at Lincoln (Table XVI), seven of these during the period of 
our connection with the Nebraska Agricultural Experiment Station. 
From the table it will be seen that the drouths so defined are especially 
likely to begin with the first day of March, or at least to include the greater 
part of that month. Of the fifteen, seven began on March 1 and two 
others covered a large part of that month. April is the month in which 
drouths are next in prominence, while May, June, July, and August have 
each played an important part in only a single drouth, and September 
in none. In so far as most crops are concerned the months of real 
drouth, those showing a marked deficiency in soil moisture as con¬ 
trasted with a deficiency in precipitation, are June, July, and August. 
The dry period in May, 1912, which did not meet the above definition 
of drouth was far more severe on vegetation than any of the seven 
drouths we had an opportunity to observe. This emphasizes the failure 
of any single weather factor to indicate satisfactorily a deficiency of 
soil moisture, or to indicate a drouth in so far as crop growth is concerned. 
Table XVI.— Drouths a during the crop season, at Lincoln, Nebr., in the 20-year period, 
1895-1914 
Series 
No. 
Year. 
Period. 
Dura¬ 
tion. 
Chief month of drouth. 
I 
189s 
Mar. 1 to Apr. 28... 
Days. 
59 
March and April. 
2 
189s 
Apr. 30 to May 30... 
3 1 
May. 
3 
189s 
June 29 to July 28. 
30 
July- 
4 
1899 
Mar. 12 to Apr. 25.. 
45 
March and April. 
5 
1900 
Mar. 1 to Apr. 14... 
45 
March. 
6 
1902 
Mar. 1 to Apr. 24. 
55 
March and April. 
7 
1 9°3 
Mar. 1 to Apr. 9. 
40 
March. 
8 
1906 
Aug. 8 to Sept. 13.. 
37 
August. 
9 
1908 
Mar. 6 to Apr. 16. 
41 
March. 
10 
i 9°9 
Mar. 1 to Apr. 5... 
35 
Do. 
11 
1909 
Apr. 7 to May 11. 
34 
April. 
12 
1910 
Mar. 1 to May 1.. 
62 
March and April. 
13 
1911 
Mar. 1 to Apr. 25 . 
Do. 
14 
1911 
June 8 to July 8. 
30 
June. 
IS 
1912 
e 
Mar. 21 to Apr. 19. 
30 
April. 
a Defined as a period of 30 consecutive days between Mar. 1 and Sept. 30 without a total precipitation of 
0.25 inch in 24 hours chart). 
SUMMARY 
The paper reports a study of the variations in moistness of the different 
inch sections of the surface foot of soil in some fields near the Nebraska 
Agricultural Experiment Station, which is near, but still within, the 
western limit of the strictly humid portion of the American prairies. The 
work was carried out during seasons which were exceptionally favorable 
