Research on mechanism of nitrogen saturation of forest soil with Nox of atmospheric origin

东、西两侧山溪硝态氮浓度存在显著差异。这可能是大都市区来源的氮氧化物的区域分布造成的。本研究利用森林氮素循环模型模拟了氮素向河流的淋溶。在该模型中，树木生长所需的氮吸收量与树木的碳量有关。仿真结果与实测值基本一致。然而，也有一些地区，在土壤中观察到的氮量不对应于观察到的氮浓度的山溪。通过实验室实验研究了这一现象产生的原因。考察了反硝化细菌数量的差异。但土壤中氮素浓度的分布形态与反硝化细菌数量的相关性尚不明确，需要进一步研究以解释土壤和河流中氮素浓度的差异。

There is a remarkable difference in the density of Nitrate-nitrogen of the mountain stream in the east and west side of Tone River. It is suggested that this phenomena is caused by regional distribution of Nox of the metropolitan area origin. This research simulated leaching to the river of nitrogen by using the nitrogen cycle model of the forest. In this model, the absorbed amount of nitrogen necessary for the tree's growing up is related to the amount of the carbon of the tree. The result of the simulation was almost corresponding to the value of the measurement. However, there were some regions where the observed amount of nitrogen in the soil did not correspond to the observed concentration of nitrogen of the mountain stream. The laboratory experiments were done looking for the reason of this phenomena. The difference of the amount of the denitrification bacterium was checked. However, the correlation between the shape of the distribution of the observed concentration of nitrogen in the soil and the amount of denitrification bacterium was not found. The further investigation is necessary to explain the difference between nitrogen concentration of soil and stream.