緩衝林帶對林地栽植檳榔之水土保育效益

Effect of Buffer Forest Strip on Soil and Water Conservation for Planting Betel Palm in Forested Land

盧惠生(Hui-Sheng Lu) ； 林壯沛(Jaung-Pey Lin) ； 林介龍(Chieh-Lung Lin) ； 王秋嫻(Chiu-Hsien Wang)

《坡地防災學報》 13卷1期 (2014/06) Pp. 1-13

摘要

於林業試驗所蓮華池研究中心，設置25%與45%兩種坡度檳榔水土流失試區，施以不同區位行帶之緩衝林帶處理，量測水土保育效益，獲得田間觀測數據，尋求最適區位行帶的緩衝林帶處理，作為今後處理國有林租地違規種植果樹之依據。水土流失試區檳榔植株胸高直徑與高度調查，坡度25%緩坡的5個小區檳榔植株，高度平均值在6.3-8.4 m間，胸高直徑平均值在9.9-10.9 cm間；坡度45%陡坡的5個小區檳榔植株，高度平均值在6.9-8.9 m間，胸高直徑平均值在10.3-11.9 cm間，顯示陡坡試區檳榔植株生長比緩坡試區稍佳。地被植生覆蓋密度調查，坡度25%緩坡地被植生覆蓋密度在42%-70%；坡度45%陡坡地被植生覆蓋密度在41%-67%，緩坡試區的各小區地被植生密度比陡坡試區的各小區地被植生密度略高。坡度25%緩坡的4個緩衝林帶處理小區各15株烏心石苗木，苗木平均高度在2.50-2.93 m間；坡度45%陡坡的4個緩衝林帶處理小區各15株烏心石苗木，苗木平均高度在1.93-2.55 m間，顯示坡度25%緩坡烏心石苗木高度平均值比45%陡坡烏心石苗木高度平均值稍大。坡度25%緩坡的5個小區土壤粗孔度在6.1%-7.4%間，總孔度在39.0%-45.3%間；坡度45%陡坡的5個小區土壤粗孔度在6.4%-7.5%間，總孔度在41.2%-46.5%間，坡度45%陡坡的土壤粗孔度與總孔度比坡度25%緩坡的土壤粗孔度與總孔度略為稍多，但差異並不明顯。降雨量為2659.5 mm，坡度25%緩坡的5個水土流失試區地表逕流深度在74.4-303.5 mm間，逕流率在2.8%-11.4%間，坡度45%陡坡的5個水土流失試區地表逕流深度在98.3-398.2 mm間，逕流率在3.7%-15.0%間，每試區15株烏心石全園間植與每試區15株烏心石下坡三行栽植之處理，其地表逕流深度與逕流率均為較小。坡度25%緩坡的5個水土流失試區土壤沖蝕量在13.1-70.7 kg間，土壤沖蝕深度在0.05-0.26 mm間，坡度45%陡坡的5個水土流失試區土壤沖蝕量在32.2-105.3 kg間，土壤沖蝕深度在0.12-0.39 mm間，每試區15株烏心石全園間植與15株烏心石下坡三行栽植之處理，其土壤沖蝕量與土壤沖蝕深度均為較小。坡度25%緩坡與坡度45%陡坡的各試區地表逕流深度、地表逕流率、土壤沖蝕深度與地被植生覆蓋密度關係成反比，故減緩地表逕流深度、逕流率及土壤沖蝕的原因，應是緩衝林帶與地被植生覆蓋密度的雙重功能。

關鍵字

水土保育 ； 緩衝林帶 ； 檳榔

並列摘要

This project was to build soil and water loss plots of betel palms under slopes 25% and 45% at Lienhuachih Research Center of Taiwan Forestry Research Institute. The soil and water loss plots had be treated with different locations of buffer forest strips for measuring surface runoff and soil erosion. From field data of surface runoff and soil erosion, the best location of buffer forest strips would be identified for helping management of illegal planting fruit trees on hillslope of national forested lands. The average heights and breast diameters of betel palms were 6.3-8.4 m and 9.9-10.9 cm for 5 plots of gentle slope 25%, as well as 6.9-8.9 m and 10.3-11.9 cm for 5 plots of steep slope 45%, respectively. Comparing with growing condition of betel palms, the steep slope was better than gentle slope. The cover densities of herbaceous vegetation were 42%-70% for 5 plots at gentle slope 25% and 41%-67% for 5 plots at steep slope 45%, respectively. The cover densities of herbaceous vegetation for 5 plots at gentle slope 25% were higher than those of herbaceous vegetation for 5 plots at steep slope 45%. The average heights of Michelia formosana buffer forest strips were 2.50-2.93 m for 4 plots of gentle slope 25%, as well as 1.93-2.55 m for 4 plots of steep slope 45%, respectively. The average heights of Michelia formosana buffer forest strips for 4 plots of gentle slope 25% were higher than those of Michelia formosana buffer forest strips for 4 plots of steep slope 45%. The macro-porosities and total porosities of soil were 6.1%-7.4% and 39.0%-45.3% for 5 plots of gentle slope 25%, as well as 6.4%-7.5% and 41.2%-46.5% for 5 plots of steep slope 45%, respectively. Comparing with macro-porosities and total porosities of soil, the steep slope was a little more than gentle slope. The surface runoff depths and rates under 2659.5 mm of annual rainfall amount were 74.4-303.5 mm and 2.8%-11.4% for 5 plots at gentle slope 25%, as well as 98.3-398.2 mm and 3.7%-15.0% for 5 plots at steep slope 45%, respectively. The surface runoff depths and rates were small for Michelia formosana planted among whole slope or Michelia formosana buffer forest strips of 3 rows planted along lower slope. The soil erosion amounts and depths under 2659.5 mm of annual rainfall amount were 13.1-70.7 kg and 0.05-0.26 mm for 5 plots at gentle slope 25%, as well as 32.2-105.3 kg and 0.12-0.39 mm for 5 plots at steep slope 45%, respectively. The soil erosion amounts and depths were small for Michelia formosana planted among whole slope or Michelia formosana buffer forest strips of 3 rows planted along lower slope. The surface runoff depths and rates as well as soil erosion depths were negative relation with the cover densities of herbaceous vegetation for gentle and steep slopes. Decreasing surface runoff depths and rates as well as erosion depths would result from both effects of buffer forest strips and cover densities of herbaceous vegetation.

並列關鍵字

Soil and water conservation ； Buffer forest strip ； Betel palm