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：对京都大学森林的7个不同年龄的人造杉木林和4个天然和落叶阔叶林的径流水化学进行了研究。每两周进行一次研究，并与降雨量进行比较。与降雨量相比，径流水中NO_3-N浓度显著降低。在径流水和降水中检测到的NH4-N、org-N和全P浓度大致相同。当径流水量减少到降雨量的2/3时，我们可以说森林净化了氮、磷等富营养化物质。1991：由于本大学森林不同林分的径流水化学成分没有明显差异，我们的研究集中在森林调节径流水化学物质的细节上。沿着森林坡面埋设离子交换树脂，并测量渗透到土壤中的水化学物质的量。在下坡，检测到的化学物质是上坡的几倍。通过蒸渗仪测定土壤水分化学成分的试验，发现土壤硝态氮沿坡面从上到下呈递增趋势。硝态氮的增加也带来了钙和镁的增加。1992：在坡度较低的50 cm土层，硝酸盐浓度较高。为了跟踪硝态氮的去向，测量了氮的天然同位素丰度比，并证实了饱和水层中的反硝化作用。在连续坡面上，土壤硝化作用和盐基饱和度在生物和环境因素的正反馈作用下发生了明显的变化。

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.