Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/33952
標題: Effect of Gravel on Soil Erosion
礫石對土壤沖蝕影響之研究
作者: 游韋菁
You, Well-Ching
關鍵字: Soil Erodibility Factor
土壤沖蝕指數
Rock
Yellow Soil
Red Soil
礫石
黃壤
紅壤
出版社: 水土保持學系
摘要: 台灣地區降雨量高,土壤沖蝕嚴重,在沖蝕過程中土壤之細顆粒較易流失,遺留下之礫石量相對增加,改變土壤之成份,對於土壤抗沖蝕能力亦有相當的影響。 為瞭解土壤礫石對於土壤沖蝕之影響,本研究利用台灣西部常見之黃壤(砂質壤土)及紅壤(坋質粘壤土)為主要土樣樣本,將過篩後之重填土(粒徑< 2mm)隨機混合或敷蓋礫石,以人工模擬降雨試驗測定土壤流失量,並以USLE公式求取實驗之土壤沖蝕指數。同時將實驗結果與土壤沖蝕指數線解圖、幾何平均粒徑法及RUSLE電腦程式等三種方式求取之土壤沖蝕指數進行比較分析。 土壤中的礫石,改變了土壤的物理性質,其中又以降低其孔隙度,間接影響其飽和水力傳導度降低土壤水分移動的速率,對於土壤沖蝕指數影響最高。二土樣又以紅壤受影響程度較大,黃壤之影響程度較小。以線解圖法、幾何平均粒徑法及RUSLE電腦程式推估混合礫石土樣之土壤沖蝕指數,均為低估之情形。 而土壤表面礫石,減少了土壤滲透之面積,減緩土壤水分之滲透,增加了逕流量。當土表之礫石量,對於土壤的保護效力,超過其增加逕流量帶來之沖蝕力時,始確實對土壤保護有正面之效益。在礫石敷蓋敷蓋率達15%時,才對土壤表面之保護產生作用,減少土壤流失。 本試驗並建立以線解圖所得土壤沖蝕指數推估不同礫石含量之土壤沖蝕指數關係式。
Due to high rainfall, soil erosion is serious in Taiwan. The fine soil particles erode easily and gradually increases the gravel content in soil after soil erosion occurs. It will change the texture of soil and affect soil erodibility. Two sieved soil samples with gravel content in soil and cover on soil surface were packed to measure soil erosion and soil erodibility factor by applying simulated rainfall and the USLE equation. The measured erodibility factors (K-values) were compared with the K-values calculated by the K-nomograph, geometric mean particle diameter, and the RUSLE program. The results indicated that, soil porosity and saturated hydraulic conductivity decreased with increasing gravel content. On the contrary, the K-values increased with increasing gravel content. The measured soil erodibility factor was slightly higher than the predicted K values using the K-nomograph, geometric mean particle diameter, and RUSLE computer program. Soil infiltration velocity and depth decreased with gravel mulching and resulted in that runoff increased. However, when the mulching rate increased to 15%, gravel mulching would protect the soil surface and reduce the soil loss. We also establish an relation function between soil and with different gravel content.
URI: http://hdl.handle.net/11455/33952
Appears in Collections:水土保持學系

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