Oil the Behavior of Nitrate in Paddy Soil. 



19 



i). Humy soil of a field, from Nishigahara, 



2). Clay soil from Kaga province. . 



3). Alluvial sandy loam soil from Arakawa, near Tokyo. 



The experiment was begun April 11, 1905, and lasted 50 days, every 

 day a portion of the contents of each flask was withdrawn to test for nitrite. 

 The room temperature was i7-25°C. During 12 days from the start slight 

 reaction for nitrite was observed in the soil (i) and (2) and then the reaction 

 disappeared. In the soil (3) no trace of nitrite was found through the whole 

 period. Thus we see that little or no nitrite formation takes place in the 

 top soil of the dry land state, especially in the sandy soil and when nitrate 

 alone was applied. 



B. Top and Sub-soil in dry land state. 



The same soils as in Experiment (A) just described served also for this 

 experiment. They yielded the following chemical and physical data : 



45O) 550 and 600 g of these soils resp. were mixed with 4 g of sodium 

 nitrate in a moderate concentration and put in glass cylinders of ^,6 cm. 

 diametre and 2/6 cm. height open at both ends, the upper half of the soil 

 in a loose condition and the lower half in a compact condition, the lower 

 end of the cylinder being closed with linen smeared with melted paraffin. 

 Besides, the cylinders were covered with black paper, sun-light being 

 allowed to reach only the surface of the soils. 



