Forest hydrological and ecological study on the effects of forest type and its stand age on the quality and quantity of forest runoff water

1990年：在京都大学森林中的7个人工杉林林分的可变年龄和4个天然落叶阔叶林林分的径流水化学进行了研究。每2周进行一次研究，并与降水量进行比较。径流中NO_3-N浓度较降水明显降低。径流水和降水中NH_4-N、有机氮和全磷的浓度基本相同。由于径流量减少到2/3的降水量，我们可以说，森林净化富营养化物质，如氮和磷。1991年：由于没有明显的差异被检测到之间的变量林分在这所大学的森林径流水化学物质，我们的调查工作集中到森林机制的细节调节径流水化学物质。将离子交换树脂沿着林坡埋置，测定土壤中渗透的水化学物质的量。在坡下部，化学物质的检测量是坡上部的几倍。利用蒸渗仪测定土壤水化学成分的试验结果表明，硝态氮含量沿坡面沿着由上而下逐渐增加。硝态氮的增加也带来了钙和镁的增加。1992年：在低坡50 cm的土壤深度，检测到高浓度的硝态氮。为了跟踪硝酸盐氮的去向，测定了氮的天然同位素丰度比，并确认了水饱和层中的反硝化作用。沿着连续坡面，土壤硝化作用和盐基饱和度随生物因子和环境因子的正反馈作用而发生变化。

1990: Runoff water-chemicals were studied in seven man-made Sugi forest stands of variable ages and four natural and deciduous broad-leaved forest stands at the Kyoto University Forests. Studies were conducted every 2 weeks and compared with that precipitation. NO_3-N concentration in runoff water decreased considerably compared to precipitation. About the same concentration of NH_4-N, org-N, and total-P were detected in runoff water and precipitation. As the amount of runoff water decreased to 2/3 of the precipitation, we can say that the forest purifies eutrophication substances such as nitrogen and phosphorus.1991: As no apparent difference was detected among the runoff water-chemicals of the variable forest stands in this University Forest, our investigation efforts were concentrated into the details of forest mechanisms in regulating runoff water chemicals. Ion exchange resins were buried along the forest slope and the amount of water-chemicals which infiltrate through the soil was measured. At lower slope, the amount of chemicals detected was several times that of upper slope. Through the experiment of soil water-chemicals measurement using lysimeter, an increase of nitrate along the slope was detected from upper to lower slope. The increase of nitrate also brought about an increase of calcium and magnesium.1992: At soil depth of 50cm in lower slope, a high concentration of nitrate was detected. To follow the fate of this nitrate nitrogen, the natural isotope abundance ratio of nitrogen was measured and denitrification in the water saturated layer was confirmed. Along a continuous slope, nitrification and base saturation in the soil changed punctually with the positive feedback interaction between biological and environmental factors.