256 NATURE AND PROPERTIES OF SOILS 



with the quantity of phosphates found in the drainage water 

 from certain soils. Some of his results are given in Table LV : 



Table LV 



Soil 



Loam 



Clay....... 



Lime soil. . . 

 Organic soil 



Eelative Produc- 

 tion of G0 2 

 (milligrams to a 

 pound of soil in 24 



HOURS) 



11 



7 



16 

 25 



Stoklasa considers that the production of carbon dioxide 

 is a measure of the intensity of bacterial action in the soil, 

 and that in consequence of this activity the phosphorus is 

 rendered soluble. 



As far as biological activity is concerned, carbon dioxide 

 seems to be a factor only insofar as it dilutes the oxygen. 1 

 This seems to be especially true of those bacterial processes 

 involved in the formation of nitrates. When it exists to the 

 exclusion of the oxygen, it produces anaerobic conditions but 

 in this respect it functions in exactly the same way as does 

 nitrogen or any other inert gas. Physiologically it seems to 

 have no detrimental effects. Carbon dioxide increases so 

 markedly with an increase in nitrate production that its 

 presence can not be depressing. 2 



133. Importance of oxygen in the soil air. — Oxygen is 

 the all-important gas of the soil air. Without it no weather- 



1 Plummer, J. K., Some Effects of Oxygen and Carbon Dioxide on 

 Nitrification and Ammonification in Soils; Cornell Agr. Exp. Sta., Bui. 

 384, Dec. 1916. 



Also, Owen, W. L., Effect of Carbonates upon Nitrification ; Ga. Agr. 

 Exp. Sta., Bui. 81, 1908. 



a Neller, J. E., Studies in the Correlation Between the Production 

 of Carbon Dioxide and the Accumulation of Ammonia by Soil Organ- 

 isms; Soil Set, Vol. V, pp. 225-241, 1918. 



Stoklasa, Julius, Methoden zur biochemischen Untersuchung des 

 Bodens; Handb. Biochem. Arbeitsmeth., Bd. 5, S. 843-910, 1912. 



