EXPERIMENT STATION BULLETINS. 



787 



TABLE 79.- MONTHLY, SEASONAI., AND YEARIA' .AVERAGE TEMPERATURE OF DIFFERENT TYPES OF 



SOIL, NOT COVERED WITH SAND. 



An examination of the foregoing tables shows the following most im- 

 portant facts: (l)In all three years the highest seasonal average tem- 

 perature occurred in the summer, a slightly lower in the spring and 

 autumn and the lowest in the winter. The fall temperature was slightly 

 higher than that of the spring. (2) In all the four seasons there was 

 a greater or less gradient of temperature at the various depths. Dur- 

 ing the seasons of spring, summer and fall this gradient diminished with 

 increase in depth but in the winter the reverse was true. (3) The mag- 

 nitude of the yearly average temperature was practically the same for 

 all types of soil and equal at all three depths, i. e., the upper 18-inch 

 layer of the different types of soil had practically the same magnitude 

 of yearly average temperature. (4) The average air temperature was 

 more or less lower than that of all the soils at any depth in all four 

 seasons. 



