Feb. j 4 . 19*3 Effect of Burning on Vegetation in Kansas Pastures 639 
Table VI. —Mean maximum and minimum temperatures at a depth of three inches on 
burned and unburned plots (1918 to 1921) 
Year. 
Mean maximum temperatures. 
Mean minimum temperatures. 
Burned. 
Unbumed. 
Difference. 
Burned. 
Unbumed. 
Difference. 
1918. 
69.9 
6l. O 
+8.9 
53-4 
SO -4 
+ 3-0 
1919 . 
65.8 
62. I 
+ 3-7 
54*7 
51-9 
+2.8 
1920. 
72. 6 
72. 8 
—. 2 
61.8 
55-5 
+6.3 
1921. 
66.6 
64. 8 
+ 1.8 
52. 1 
47-3 
+4. 8 
Average. 
68.7 
65. 1 
+ 3*6 
55*5 
5 i -3 
+4. 2 
In every year, as shown in Table V, the mean maximum temperature 
of the soil at a depth of one inch, averaged materially higher on the 
burned plot. This difference ranged from 4.5 0 F. in 1919, to 18.6° in 1920. 
The average difference was 12.1 °, A higher mean minimum temperature 
was also recorded for the burned plots except in 1918, when the difference 
was negligible. The average difference it will be noted is 4.1 °. 
Similar, although less marked differences were recorded at a depth of 
three inches (Table VI), where the average difference in the mean maxi¬ 
mum temperature was 3.6°F. and in the mean minimum temperature 4.2 °. 
These results show beyond a reasonable doubt that the soil on the burned 
plots absorbed more heat, which no doubt explains the earlier growth of 
vegetation previously pointed out. 
As shown in figures 1, 2, 3, and 4, the burned plots were consistently 
warmer throughout the season than the unbumed plots, as measured by 
the weekly mean maximum temperatures at a depth of one inch, with a 
few exceptions. The mean minimum temperatures were also in favor 
of the binned plots. It appears that the differences in early growth of 
vegetation may easily be accounted for by these differences in tem¬ 
perature. i@R si 
EFFECT OF BURNING ON THE YIEUdJofJhAY 
The yield of hay was usually determined about September 10, each 
year, by harvesting several areas, usually ten in number. These areas, 
each one-ten-thousandth of an acre, were selected by means of the iron 
hoop previously mentioned. HIP 
The results expressed in pounds of dry matter per acre are shown for 
each year in Table IX. 
Table IX. —Showing the yields of cured hay on burned and unburned plots (1918 to 1921) 
Pounds per acre. 
Year. 
Burned. 
Unbumed. 
Difference 
(in favor of 
burned). 
3 .07s 
3 , 5 °° 
1.730 
3.156 
2.865 
4.623 
3.633 
h 774 
2,973 
3.251 
-1,548 
-133 
-*44 
JQ21 . 
+183 
-386 
Average.. 
