718 



PRINCIPLES OF SOIL MICROBIOLOGY 



by the amount of oxygen absorbed, varied with fertility and suggested 

 using the former as a measure of the latter. Oxidation was influenced 

 by soil temperature and moisture and content of calcium carbonate. 

 Stoklasa and Ernest 20 placed 1-kgm. portions of sieved soil in a glass 



1(6) 



Fig. 58. Apparatus for determining the COj-production in field soil: a, Zinc 

 bell, in side view; b, arrangement for taking sample (R = Recipient) (from 

 Lundegardh). 



20 Stoklasa, J., and Ernest, A. Uber den Ursprung, die Menge und die Bedeu- 

 tung des Kohlendioxyds irn Boden. Centrbl. Bakt. II, 14: 723-736; Ztschr. 

 Zuckerind. Bohmen., 31: 291-401. 1911; Stoklasa, J. Methoden zur Bestim- 

 mung der Atmungsintensitiit der .1'akterien im Boden. Ztschr. Landw. Ver- 

 suchst. Oesterreich., 14. 1911, 1243-1279; also Chem. Ztg., 46: 681-683. 1922. 



