492 



EXPERIMENT STATION RECORD. 



In 1892 observations of a similar nature were made on two samples 

 of soil of the Liinagne of Auvergne — one from Marmilhat and the other 

 from Palbost. Examinations of the drainage water from pots of these 

 soils gave the following results : 



Nitric nitrogen per cubic meter of drainage water. 



July 21, 1892 



September 21, 1892 . 



Marmilhat. Palbost. 



Grams. 

 884 

 250 



Gramt. 

 140 



285 



The results of the first determinations are very high. For compari- 

 son the results obtained on other soils in 1890 and 1891 are added: 



Nitric nitrogen per cubic meter of drainage water. 



Wardrecqiies soil. 

 Blaringliem soil . . 



1890. 1891, 



Grams. 

 116 



108 



Grams. 

 33 

 39 



When these results are combined and studied the interesting fact is 

 brought out that nitrification is very active in soils recently put under 

 experiment. This confirms an opinion expressed some time ago by 

 Schlosing in discussing a memoir of Coren winder published in 1856, 

 which stated that in stirred and pulverized soils the production of car- 

 bonic acid was more raj)id than in undisturbed soil. This accelerated 

 combustion was attributed to the freer circulation of oxygen in the 

 stirred soil, but Schlosing denied this. He stated that stirring the soil 

 favored the spread of organisms which are the agents of combustion. 

 It is evident, he stated, that in a liquid medium the microscopic organ- 

 isms are able to move freely from place to place and to act ui3on every 

 portion of the material, but in the soil they do not possess this unre- 

 stricted power of locomotion. They are found only on the surface of the 

 particles of moderately moist soils where the very thin film of moisture 

 is decidedly unfavorable to their movement from place to place, and con- 

 sequently, wnen the food at any given point is exhausted the activity 

 of the organisms is checked. If the soil is stirred the organisms are 

 scattered and find new supplies of nourishment, and their activity 

 develops again. Schlosing extended this hypothesis to the explanation 

 of the phenomenon of nitrification, but it was not until many years 

 afterwards that experiments on the pulverization of the soil by the 

 author called attention to the importance of this suggestion. 



This effect of pulverization was not clearly observed in soils kept in 

 the laboratory and which had been subjected to various manipulations, 

 such as sampling, grinding, sifting, etc. These operations so thoroughly 

 disseminated the ferments that subsequent pulverization produced little 

 effect. It was quite otherwise, however, with soils which had been left 

 undisturbed in place and afterwards pulverized and stirred. 



