SOIL HEAT 



321 



temperature, influenced, of course, by the conditions 

 already discussed. The effect of this heat supply is re- 

 flected in the seasonal, monthly, and daily soil tempera- 

 tures at the surface and at varying depths below. The 

 following data illustrate the differences that may ordi- 

 narily be expected to take place from season to season on 

 an average soil : 



AVERAGE TEMPERATURE READINGS TAKEN AT BRESLAU, GER- 

 MANY. 1 AVKUAGB OF TEN YEARS, 1901-1910 (IN DEGREES 

 FAHRENHEIT) 



AVERAGE TEMPERATURE READINGS TAKEN AT LINCOLN, NE- 

 BRASKA. 2 AVERAGE OF TWELVE YEARS, 1890-1902 (IN 

 DEGREES FAHRENHEIT) 



1 Schulze, B., and Burmester, H. Beobochtungen uber 

 Temperaturverhaltnisse der Bodenoberfliiche und verschiedener 

 Bodentiefen. Internat. Mitt, fur Bodenkunde, Band II, Heft 

 2-3, Seite 133-148. 1912. 



2 Swezey, G. D. Soil Temperatures at Lincoln, Nebraska. 

 Nebraska Agr. Exp. Sta., 16th Ann. Rept., pp. 95-102. 1903. 



