482 SOILS; PROPERTIES AND MANAGEMENT 



which is of the greatest benefit to the soil in maintaining 

 a slight alkalinity very favorable to the development of 

 many beneficial bacteria and to the maintenance of good 

 tilth. 



Stoklasa * has correlated the carbon dioxide production 

 with the quantity of phosphates found in the drainage 

 water from certain soils. Some of his results are given 

 below : — 



P2O6 in Drainage 



Water 



(Kilograms to a hectare) 



Relative Produc- 

 tion of COl 

 (Milligrams to a kilo- 

 gram soil in 24 hours) 



Loam . . 

 Clay . . 

 Lime soil 

 Humous soil 



24 

 15 

 36 

 56 



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 phos- 

 phorus is rendered soluble. 



When carbon dioxide is combined as sodium carbonate 

 or potassium carbonate in considerable quantity, as in 

 certain alkali soils, a very injurious action on plant roots 

 and on soil structure results. On plants the carbonate 

 acts as a direct poison (see par. 305). The effect on 

 soil structure is to deflocculate the particles producing 

 the separate grain or the compact arrangement (see par. 

 420). 



1 Stoklasa, J. Methoden zur Bestimmung der Atmungs- 

 intensitat der Bakterien im Boden. Zeit. f. d. Landw. Versuchs- 

 wesen in Oesterreieh, Band 14, Seite 1243-79. 1911. 



