Corn Investigations 
141 
one foot above the ground. The soil temperature record is for a 
depth of three inches, which corresponds with the depth at which 
the seed was planted. The instruments were fully surrounded by 
a normal stand of corn in a representative portion of the field. 
The data in Table 60 indicate that the soil temperatures ap- 
proximated closely the prescribed temperatures for disease tests 
made in the germinator and were favorable for disease develop- 
ment. Together with the very favorable soil moisture which 
prevailed, this provided soil conditions conducive to the de- 
velopment of the rot diseases. 
Table 60. — Soil and air temperatures in the cornfield in which 
the root-rot disease studies reported in Table 57 were made. 
1021. 
Mean hourly temperatures 
Week ending 
Air temperature one foot 
above ground 
Soil temperature three inches 
below surface 
x Night 
x Day 
Maximum 
Night 
Day 
Maximum 
Deg. F. 
Deg. F. 
Deg. F. 
Deg. F. 
Deg. F. 
Deg. F. 
(1) 
(2) 
(3) 
(4) 
(5) 
(6) 
(7) 
May 29 
75.2 
84.8 
94.4 
73.7 
76.3 
83.6 
June 5 
69.1 
71.4 
80.1 
71.6 
73.4 
78.9 
June 12 
71.0 
79.1 
85.1 
74.4 
78.1 
85.3 
June 19 
78.8 
87.7 
94.1 
83.6 
86.3 
93.9 
June 26 
74.7 
81.3 
91.9 
83.3 
82.6 
91.7 
July 3 
80.5 
84.8 
97.3 
83.2 
82.7 
89.7 
July 10 
74.0 
80.3 
88.7 
77.3 
78.3 
81.7 
July 17 
74.4 
79.9 
85.4 
82.6 
83.0 
86.7 
July 24 
70.3 
76.7 
81.1 
77.6 
77.8 
80.9 
July 31 
72.7 
79.2 
85.9 
79.9 
80.1 
84.1 
August 7 
64.1 
70.2 
76.3 
74.6 
74.3 
77.9 
August 14 
72.6 
83.0 
89.3 
74.9 
75.3 
78.9 
August 21 
70.7 
77.3 
82.3 
74.0 
74.1 
78.9 
August 28 
75.6 
80.0 
90.0 
77.8 
77.5 
82.1 
September 4 
81.9 
83.1 
96.0 
78.8 
77.2 
81.6 
Average for season 
73.7 
79.9 
87.9 
77.8 
78.5 
83.7 
x Night period was from 8 P. M. to 8 A. M. Day period was from 8 A. M. 
to 8 P. M. 
