i8 



G, Daikiiliitfu, and T. Iinaseki. 



From the above figures the loss of nitrogen by the reduction of nitrate 

 was calculated with the result shown in the foUowingr tables : 



This result confirms the observations made by occasional testing as 

 above stated and clearly shows that the starch, rape cake and straw very 

 much favor denitrification in the paddy soil, while well rotten compost 

 especially when sterilized has far less influence upon denitrification. 

 But little loss of nitrogen took place in flask II to which nitrate alone 

 was applied, perhaps by the accidental absense of the denitrifying microbes 

 proper. 



LABORATORY EXPERIMENT VI. 



To observe whether nitrate formation and denitrification^' take place 

 in the dry land state, the following experiments were carried out. 



A. Dry land top soil. 



One hundred g of the following three samples of soil were placed in 

 Erlenmeyer's flasks of ca. 300 cc. capacity with 2 g of sodium nitrate in 

 solution and kept in a moderately dry condition, and in control flasks the 

 same amount of distilled water was applied : 



i). Nitrite formation is frequency the first step of denitrification with loss of nitrogen. In 

 certain cases however the nitiite may be completely reduced to ammonia. 



