July, 1917.] 



GROWTH OF APPLE TREES. 



9 



ture, but the fact that it has no covering is probably the most 

 important cause. This relationship is seen in Table No. 3. 



TABLE No. 3. 



Average Soil Temperatures and Average Per Cent 

 Moisture Per Plot Woodman Orchard. 



1916. 

 At 8 inches. 



In the subsoil which is recorded at 3 feet below the surface we 

 find each month that the sod plot (No. 1) is lower than the other 

 two plots recorded (Plots 4 and 7), with an average for the season 

 of 54.89. Plot 7 is the highest each month, except in September, 

 which is not true with the surface soil. However, there is only 

 a slight difference between Plots 4 and 7 in this regard, and the 

 average difference for the season is only .67 of one degree. See 

 Table No. 2. 



The soil moisture in this case shows the highest per cent obtains 

 where the temperature is highest, and the lowest temperature 

 where the moisture is intermediate. In other words, no correla- 

 tion seems to exist between these two factors in the subsoil, where 

 of course no evaporation is taking place. For complete data on 

 the soil temperature see Table No. 5. 



The same general conclusions can be drawn from the actual 

 depth of freezing as were drawn from the temperature of the 

 surface soils. On March 6, 1916, the soil was frozen as deep, 



