(>1 



SOIL TEMPERATURES OBSERVED AT AUBURN, ALA. 



As an illustration of soil temperatures in a southern locality I 

 have chosen the following record for 1880 at Auburn, Ala., where 

 the agriculiural experiment station has maintained three sets of 

 buried thermometers, two of them in sandy soils on hills and one in 

 moist bottom land near the banks of a small stream. It appears 

 from these records that the dilt'erence in temperature in the growing- 

 season between the so-called " cold wet "" and '' warm dry " soils 

 averages but a few degrees; in fact, I doubt whether it is appreciable 

 from observations having the accurac5^ of those here given. Thus 

 at 3 inches depth and during the warm half of the year the maxi- 

 mum temperatures on the hill average 1° F. above those in the 

 bottom land, while the mininnim temperatures on the hill average 

 2° F. colder than 4liose of the bottom lands. The temperatures here 

 given are the averages of the maxima and minima and are taken 

 from successive monthly reports and from Bulletin No. 18 of the 

 Alabama Agricultural Experiment Station. In these, as at most 

 other United States stations, the correction for the temperature of 

 the long stem of the thermometer still remains to be applied. A com- 

 })arison of the temperature at o inches depth with the maximum 

 and minimum air temj^erature shows that the soil is Avarmer than 

 the air in the daytime from April to October, inclusive, and 

 warmer than the air at the minimum temperatures throughout the 

 year. This latter is true for the minimum temperatures of the soil 

 down to a depth of 96 inches, but the excess of maxima temperatures 

 of the soil over those of the air during the daytime in summer 

 ceafses a little below (> inches. Evidently the temperature of the soil 

 is sufficiently high to allow of the growth of some form of vegeta- 

 tion throughout the year. 



Edtrcinci and means of soil tciiiiicrninrcs for 1SS9, as ohscrrrd a I Aiihiini, Ala. 

 [Lat. :'.L'°.G N. ; long. 85°. 4 W. ; altitude, T.i-2 feet. | 



