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

Tone河东侧和西侧山溪中硝酸盐氮的密度存在显著差异。认为这种现象是由都市圈起源的氮氧化物的区域分布造成的。本研究利用森林氮循环模型模拟氮向河流的淋滤。在这个模型中，树木生长所需的氮吸收量与树木的碳吸收量有关。仿真结果与实测值基本吻合。但也有部分地区土壤中氮的观测量与山溪中氮的观测浓度不一致。为了寻找产生这种现象的原因，进行了室内实验。检查了反硝化菌数量的差异。然而，观察到的土壤中氮浓度的分布形状与反硝化细菌的数量之间没有相关性。为了解释土壤和河流氮浓度的差异，有必要进行进一步的研究。

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.