Conservation of Water Related Environment of Watersheds with Agriculture and Forestry Landuse in Cold Region.

点击翻译按钮获取中文摘要

In this project, researches were made on water and material circulation, water use and rural area management, sustainable agriculture and environmental conservaion for the agricultural and forest area in cold regions.1) Relation between land use and river water quality was investigated on Shubuto river basin, southwestern Hokkaido. Watershed including agrictural land shows high concentrations on water quality when the amount of retained water in the watershed gets less.2) Characteristics of changes in water quality during snowmelt period were investigated using the principal component analysis.3) The effect of circulating irrigation system to the water quality and material balance were examined in lowland area of Tsugaru, Aomori. Not only the output of water, but also the output of eutrophic substances to the lakes and rivers of lower raehes were reduced due to circulating irrigation.4) Regional characteristics of T-N, T-P and dissolved SiOィイD22ィエD2 concentration in river water of Hokkaido during snow melt period was investigated in conjunction with land use and soil type of each watersheds.5) Study on ion composition of snow and snowmelt water from bottom of snow cover was tested in the forest area of northern Hokkaido. It was shown that the ion component are easily released from the snow at the early stage of snowmelt period.