July, 1917.] 



GROWTH OF APPLE TREES. 



TABLE No. 2. 

 Average Soil Temperatures Woodman Orchard. 



1916. 

 At 3 feet. 



By referring to the curves on Chart No. 1, it will be seen that 

 the sod plot started at 11 degrees colder than the clean culture 

 plot, but with an occasional exception the difference was not 

 more than 2 to 5 degrees, until early in June when they ran much 

 the same for a fortnight. Toward the end of June (22d)* the 

 clean culture plot (Plot 4) was plowed and it again ran higher 

 throughout the season than the sod plot as no cover crop is grown 

 on Plot 4. It is noticeable from the curves that Plot 4 responds 

 in a much greater degree to the fluctuations of the air temperature 

 than the sod plot, making a difference of 9 on July 13. The 

 greatest average difference in temperature occurs in April, 4.7, 

 and the lowest in June, 1.8. For May, 3.2, for July, 2.9, for 

 August, 3.0, for September 2.6. 



It may be that the low temperature in Plot 9 during the period 

 of cultivation may in part be due to its higher moisture content. 

 A greater evaporation from the soil would cause a lower degree of 

 temperature and this plot ranks a little higher in moisture than 

 any of the five plots under discussion. Plot 4 which is highest 

 in temperature in July, August and September is lowest in mois- 



*This date was very late. Owing to wet weather it was impossible to get 

 on this soil earlier. 



