SOIL ORGANISMS 



401 



The data are expressed in pounds to the acre and are averages 

 of ten years' experimentation. The carbon was lost as the 

 bicarbonate, only traces of carbonates being present. (See 

 table LXXXVIII, page 402). 



I ft ^0 2 



ANIMAL: 



GREEN FARM 



MANURE MANURE 



v V 



- DECAY 

 PARTIALLY DECOMPOSED 

 MATERIALS 



OTHER BIOLOGICAL 

 ACTIVITIES 



LEACHING 

 LOSSES 



CHEMICAL 

 REACTIONS 



Fig. 57. — Diagram showing the transformations of carbon, commonly 

 spoken of as the "carbon cycle. " 



It is apparent that a drainage loss of about 1200 pounds 

 of bicarbonate (HC0 3 ) may be expected each year to the 

 acre, without considering the carbon dioxide which is respired 

 to the atmosphere. This latter loss probably at least equals, 

 if it does not greatly exceed, the loss of carbon in the bicar- 

 bonate form. Together they cause a disappearance of several 

 hundred pounds of carbon a year under the conditions main- 



