808 



STATE BOARD OP AGRICULTURE. 



TABLE 89.— MONTHLY, MAXIMUM, MINIMUM. AMPLITUDE AND AVERAGE TEMPERATURE OF SOIL AT 



VARIOUS TOPOGRAPHIC POSITIONS. 



An inspection of the foregoing table shows that from March up to 

 about September the average temperature of the south slope was about 

 2°F higher than that of the north and top hill, about 5 or C°F than that 

 of the river bank, and about 4 or 5°F than that of the muck up to June. 

 From October on all the different locations had practicaHj the same 

 magnitude of temperature. As a rule, the greatest amplitude occurred 

 in the south and north slope and high point, and the smallest in the river 

 bank and low land or muck. 



The daily records show that the temperature of the south slope would 

 begin to rise earlier and faster in the morning during the spring months 

 than that of the north. The reason for this is obvious. 



The marked influence of the slant of the surface with respect to the 

 position of the sun on the soil temperature is even manifested on a culti- 

 vated soil with a very rough and uneven surface. Observations made 

 upon this point have yielded some exceedingly interesting and surprising 

 results. Thus, for instance, it was found that that side of the lumps 

 which faced the sun in the morning would possess as much as 5°F higher 

 temperature than that side which was shaded. Even greater differences 

 than these were obtained between the shaded and unshaded sides of a 

 dead furrow. If the soil was sandy, the side facing the sun w^ould thaw 

 almost completely and its temperature would rise several degrees above 

 the freezing point before the opposite side began to thaw. 



