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管理放棄されたヒノキ人工林小流流における物質収支の定量的把握と自然浄化機能の検討

废弃柏树林小溪物质平衡定量认识及自然净化功能研究

基本信息

批准号：
04J06809
负责人：
井手淳一郎
金额：
$ 1.79万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for JSPS Fellows
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

間伐などの施業が行われず放置されたヒノキ人工林(非管理ヒノキ人工林)は,林冠が閉鎖し,下層植生が貧弱となりリター層の発達も不十分となるため,表土流亡が起こりやすい。したがって,土粒子に吸着しやすいリン(P)は,頻発する土壌浸食によって非管理ヒノキ人工林から多量に流失することが予測される。一方,Pの年流出量(支出)は年降水量に依存すると考えられる。本研究では,50年生の非管理ヒノキ人工林流域において,多雨年(年降水量:2251mm)と少雨年(年降水量:1383mm)についてPの物質収支を評価した。年間の全リン(TP)の収支では,支出が降水による収入を多雨年で約7倍,少雨年で約2倍上回った。TPの支出のうち懸濁態リン(PP)の占める割合は多雨年で55%,少雨年で69%であった。これらの結果から,多雨年,少雨年ともに多量のPPが流失していたことが明らかとなった。月別のP収支の結果から,多雨年では8つの月において,溶存態リン(DP),PPの月間支出がともにTPの月間収入を上回っていた。一方,少雨年においてDP,PPの月間支出がともにTPの月間収入を上回ったのは7月と9月の2つの月においてのみであった。しかしながら,9月は台風にともなう記録的な集中豪雨のために,少雨年におけるTPの支出の約40%にあたるPPが流失していた。林床被覆の少ない河道沿いの土壌表層に蓄積されたPが,集中豪雨による表面浸食によって多量に河川に供給された可能性がある。本研究の結果から,非管理ヒノキ人工林では,少雨年であっても集中豪雨があれば,多量のPが流失することが示唆された。

In the operation of forest cutting, the plantation (non-management plantation) was placed, the canopy was planted, the plant growth was weak, and the topsoil exiled in exile. The soil particles sucked in the soil particles, the soil particles were soaked in the soil, the soil particles were soaked in the soil, the soil particles were soaked, the soil particles were not managed, the plantation On the one hand, the annual outflow (expenditure) and the annual precipitation depend on each other. In this study, 50-year-old unmanaged forest watersheds, rainy years (annual precipitation: 2251mm), rainy years (annual precipitation: 1383mm), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: 1383mm), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: 1383mm), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: annual precipitation), rainy years (annual precipitation: 1383mm). The total annual expenditure (TP) is about 7 times as much as that in rainy years and 2 times that in rainy years. The expenditure of TP accounts for 55% in rainy years and 69% in rainy years (PP). The results showed that in rainy years and less rainy years, the loss of PP was much higher than that in rainy years. In rainy years, monthly expenditure was recorded in 8 months, DP was recorded in 8 months, and monthly expenditure in PP was recorded in TP monthly. On the other hand, in years with less rain, monthly expenditure in DP,PP is recorded in monthly TP in July to September in the last month. In September, heavy rain and heavy rain were recorded in Taiwan. In years of light rain, the expenditure of TP was about 40%. There was a loss of PP. The forest bed is covered with a small amount of water. Along the soil surface, the forest bed is stored along the soil surface, concentrated in heavy rain, the surface is immersed in water, and a large amount of river water is supplied to the river. The results of this study showed that the artificial forest was not managed, the heavy rain was concentrated in rainy years, and a large amount of heavy rain was lost.