ip/o] CARBON, PHOSPHORUS AND NITROGEN IN SOILS 93 



The ratio of carbon to nitrogen in the original material was: 

 peat 22.7; compost 15.0; soil 24.7 and mould 12.8. He concluded 

 that the more insoluble the compound the wider was the carbon- 

 nitrogen ratio. The potassium hydroxid showed a tendency to dis- 

 solve the compounds rich in nitrogen. 



Pagnoul (51) found no fixed relation between the carbon and 

 nitrogen of the soil but apparently the carbon, nitrogen, and humus 

 varied in the same direction, altho irregularly. 



Rimbach (53) concluded that, since the matiere noire was 

 readily nitrified it was the direct source of the nitrates of the soil 

 and thus the insoluble carbon was of insignificant value. 



Frear and Hess (54) found that lime caused a more rapid loss 

 of carbon than of nitrogen in manured land, but the reverse in un- 

 manured land. 



Dyer (55) studied the carbon and nitrogen content and the re- 

 lationship between carbon and nitrogen in the soil taken from 22 

 different plots of the Rothamsted experiment fields. These data 

 are furnished for each individual Q-inch section to a depth of 90 

 inches. 



The carbon and nitrogen contents of the higher depths were 

 higher than those of the lower depths and the ratio of carbon to 

 nitrogen is wider in the former. At the fifth to sixth depth the 

 carbon and nitrogen contents seem to become fixed quantities and 

 are apparently those derived from the original matter out of which 

 the soil was formed. 



A study of various clays and other material taken from great 

 depths seemed to indicate that a nitrogen content of .04 percent 

 was indigenous to the subsoil of the Rothamsted station. 



Cameron and Breazeale (61) investigated the three general 

 methods for determining the carbon content of the soil : namely, 

 the "loss on ignition" method, the humus method and two forms 

 of a combustion method. They concluded that the first two meth- 

 ods were unreliable : the first, because there was no apparent re- 

 lationship existing between the results obtained and the true carbon 

 content ; the second, since it makes no pretense of giving the total 

 carbon in the soil. 



It is interesting to note that they reported that the ammoniacal 

 extract contained so much suspended material that it was found 

 undesirable to work with, until it was passed through a Chamber- 

 land-Pasteur filter, when a perfectly clear solution was obtained. 



Konig (67) recently studied the influence of hydrogen peroxid 

 on the organic matter of the soil. He found that it consisted of 

 two parts, one easily oxidized by hydrogen peroxid, the other not 

 oxidized by this reagent. 



