On tlie Behavior of IVitratt* in Patldy Soil. 21 



sub-soil in dry land state, while in the top-soil when kept in a loose condition 

 almost no reduction of nitrate occurs if nitrate alone is applied to the field. 



(C). The dry land state with application of some organic substance. 



In order to determine the influence of the presence of some organic 

 matter in the soil in diy land state upon denitrification, the following 

 experiment was made with the three soils mentioned below : 

 i). Humy top-soil from a field of Nishigahara. 

 2). Clayey sub-soil „ „ „ 



3). Alluvial sand soil from Arakawa. 



The cylinders of the diametre of 4 cm. and of the height of 55 cm. open 

 at both ends, were filled with each soil in the air dry state, upper layer 

 of 25 cm. deep in loose condition and lower layer of 30 cm. deep in compact 

 condition. The soils of the first series were mixed with a solution of 

 sodium nitrate and those for the second series with the same nitrate solution 

 and starch, the ratio of both the nitrate and starch to the soil being i : 100. 

 The soils were kept moderately moist and the lower open end of the 

 cylinder was covered with filter paper and linnen and kept air tight with 

 melted paraffin. The sides of the cylinders were covered with black 

 paper. 



The experiment was begun Oct. 5, 1905, and was finished Nov. 24, 

 during the first period of which every two days, and later on every 10 days, 

 a portion of the upper and lower layers of the soil was taken out by boring 

 and tested for nitrate, nitrite and ammonia with the following result : 



(i). In the humy top-soil to which both the nitrate and starch were 

 applied, much nitrate was present in the upper layer during the whole period, 

 while in the lower layer the nitrate decreased gradually and after 20 days 

 only a trace of it was observed. The soil to which nitrate alone was applied 

 showed a strong reaction for nitrate in both upper and lower layers until the 

 end of the experiment. As to nitrite a trace of it was found in the lower 

 layer during the first period in all cylinders which received nitrate and the 

 reaction disappeared after 12 days in the cylinder to which the nitrate 

 solution alone was applied, while in the cylinder to which both nitrate and 



