20 



G. Daikiiliara. and T. Iinaseki. 



The experiment was begun April 12, 1905, and every 2 days in the 

 first period and every 5 days in the later, a portion was withdrawn from the 

 upper and lower layers and tested for nitrate, nitrite and ammonia with the 

 following result : 



(i). In the humy soil to which sodium nitrate was added a little 

 nitrite was observed after 2 weeks, increasing a little afterwards, and the 

 reaction was always stronger in the sub-soil than in the top-soil. The 

 reaction for ammonia was observed after one week and was always stronger 

 in the top-soil. 



In the control case, however, no nitrite was found through the whole 

 period ; after one month a trace of ammonia and after 50 days a trace of 

 nitrate was observed. 



(2). In the clay soil to which sodium nitrate was added, a little nitrite 

 was observed after 2 days from the start, the reaction in the sub-soil 

 increasing gradually, reaching the maximum after 2 weeks and remaining 

 the same through the whole period, while in the top-soil no further increase 

 was noticed. Much ammonia was found after two days from the start, the 

 reaction of which was always stronger in the top-soil, just as with the humy 

 soil (i). In the control case, neither nitrate nor nitrite was formed through 

 the whole period, but a trace of ammonia was found after one month, a little 

 more in the top-soil than in the sub-soil. 



(3). In the sandy loam to which sodium nitrate was added, a trace of 

 nitrite was observed in the sub-soil after 3 days from start, and the reaction 

 increasing gradually, reached the maximum after 2 weeks, while in the 

 top-soil only a slight reaction for nitrite was observed after 2 weeks. With 

 regard to ammonia, only a trace of it was found after one week which 

 remained constant through the whole period. In the control case, neither 

 nitrate, nor nitrite was found through the whole period and not even a trace 

 of ammonia was found. 



The second experiment was carried out with the same soil and cylinders 

 for a longer period viz. five months (June 26 — October 28, 1905), the result 

 of which exactly coincided with that of the former experiment above 

 stated. Thus we see that denitrification takes place more or less in the 



