范正成臺灣大學：生物環境系統工程學研究所吳明峰Wu, Min-FonMin-FonWu2007-11-272018-06-292007-11-272018-06-292006http://ntur.lib.ntu.edu.tw//handle/246246/55976本研究的主要目的在於藉由人工降雨沖蝕試驗探討石塊覆蓋率及石塊放置方式對紋溝間土壤沖蝕之影響機制。沖蝕試驗採用台灣北部地區的紅壤及黃壤土，重模於沖蝕試驗箱，並分別利用天然卵石及人造水泥圓球鋪放在土壤表面模擬石塊覆蓋。覆蓋率於65%以下區分六種比例；石塊放置方式採用全部露出及半嵌入土壤表面兩種。試驗坡度則固定為20%。 試驗結果顯示，石塊覆蓋對於抑制紋溝間土壤沖蝕之效果，因覆蓋率而不同，且與其係完全露出或半嵌入土壤表面而異。完全露出土壤表面之石塊，對於抑制沖蝕之效果，優於半嵌入土壤表面之石塊。至於覆蓋率增加，則非必然可降低土壤沖蝕。本研究尚發現，在相同覆蓋率情況下，石塊半嵌入土壤表面時之沖蝕率與完全露出時之沖蝕率之比例，與覆蓋率具有自然指數關係。另在飛濺沖蝕之影響方面，完全裸露土壤之飛濺沖蝕量縱然不會全部成為進入紋溝的土壤沖蝕量，但在數量上已佔土壤沖蝕量之比例逾三分之一，甚至在低降雨強度時，其數量足以使飛濺成為沖蝕的主因。然而，隨著覆蓋率增加，飛濺沖蝕量所佔總沖蝕量之比例逐漸降低。此外，完全露出土壤表面之石塊底下受遮蔽之土壤表面，在降雨過程中因未封鎖孔隙而具有較高之滲透性。本研究所使用兩種土壤之試驗結果均顯示，經降雨沖蝕之後，石塊下方遮蔽範圍內之入滲率約為裸露土壤表面之2.2倍。The main purpose of this study is to investigate the effects of cover rate and disposition of rock fragments used as mulch cover on the mechanism of interrill soil erosion by tests with simulated rainfall. There were two kinds of soil used in this study, lateritic soil and yellow soil, and were collected from northern Taiwan. The soil was remolded in a test box. Natural pebbles and motar balls were placed at the soil surface as the mulch cover respectively. The erosion tests were repeated on soil samples at 6 different cover rates under 65%, and two types of surface covers: completely exposed to the soil surface and half embedded into the soil. During the tests, the slope steepness of the erosion boxes was maintained at 20%. It was found that the effect of reducing interrill soil erosion changed with different cover rates, and with the positions of rock fragments. The rock fragments placed on top of the soil surface were found better for controlling interrill erosion. However, the increase of cover rate did not insure reduced interrill erosion. It was also found that there was natural exponential relationship between the interrill erosion of the soils with rock fragments on top of the soil surface and with half embedded. Aside from these, even though the splash erosion would not totally become interril erosion. For soils without any cover, the proportion of splash erosion to total interrill erosion was more than one-third. At lower rainfall intensity, splash erosion dominated interrill erosion. However, along with the increase of the rates of cover by rock fragments, the proportion of splash erosion to total interrill erosion was reduced. Besides, rock fragments placed on top could protect the underlying topsoil against surface sealing by raindrop impacte, and retained higher infiltration. The results of both kinds of soil used in this study showed that the infiltration rate of the topsoil underlying the rock fragments was 2.2 times the infiltration rate of bare area after rainfall erosion.目 錄 謝誌 Ⅰ 中文摘要 Ⅱ Abstract Ⅲ 圖目錄 Ⅷ 表目錄 XI 第一章 研究動機與目的 1 1.1 研究動機 1 1.2 研究目的 2 第二章 文獻回顧 4 2.1 紋溝間土壤沖蝕發生機制 4 2.2 降雨強度對紋溝間土壤沖蝕之影響 8 2.3 石塊覆蓋對土壤沖蝕之影響 12 2.4 土壤表面孔隙封鎖對滲流及飛濺沖蝕之影響 24 第三章 石塊覆蓋對紋溝間沖蝕之影響 27 3.1 試驗材料與試驗設備 27 3.1.1 土壤 27 3.1.2 覆蓋物 30 3.1.3 沖蝕試驗箱 30 3.1.4 人工降雨機 32 3.2 沖蝕試體製作 37 3.3 人工降雨沖蝕試驗 41 3.3.1 試驗說明 41 3.3.2 試驗結果 44 3.4 入滲分析 46 3.4.1 降雨強度對滲透性之影響 46 3.4.2 石塊位置對滲透性之影響 50 3.4.3 滲透性與石塊覆蓋率之關係 51 3.5 土壤沖蝕量分析 61 3.5.1 石塊位置對土壤沖蝕量之影響 61 3.5.2 土壤沖蝕與石塊覆蓋率之關係 66 3.6 綜合性推估公式 72 3.6.1 模式之建立 73 3.6.2 迴歸分析結果 74 3.6.3 石塊完全露出與半嵌入土壤表面之沖蝕量比例關係 78 3.7 小結 80 第四章 石塊覆蓋對飛濺沖蝕與逕流沖蝕之影響 84 4.1試驗材料與試驗設備 84 4.1.1 土壤 84 4.1.2 覆蓋物 86 4.1.3 飛濺沖蝕收集系統 86 4.2 沖蝕試體製作 88 4.3 人工降雨沖蝕試驗 91 4.3.1 試驗說明 91 4.3.2 試驗設備 92 4.3.3 試驗結果 95 4.4 入滲分析 96 4.4.1 石塊完全露出土壤表面之滲透性 100 4.4.2 石塊半嵌入土壤表面之滲透性 101 4.5 逕流分析 103 4.5.1 逕流率與覆蓋率之關係 103 4.5.2 濺失雨量探討 107 4.6 飛濺沖蝕分析 111 4.6.1 飛濺沖蝕與覆蓋率之關係 111 4.6.2 飛濺沖蝕與降雨強度之關係 115 4.7 逕流沖蝕分析 118 4.7.1 逕流沖蝕與覆蓋率之關係 120 4.7.2 逕流沖蝕與降雨強度之關係 124 4.8 逕流沖蝕與飛濺沖蝕之比較 125 4.9 小結 129 第五章 結論與建議 131 5.1結論 131 5.2建議 132 參考文獻 134 附錄A 人工降雨沖蝕試驗數據（第三章之試驗） 143 附錄B 預測土壤沖蝕量與試驗量測資料比較圖（第三章之試驗） 145 附錄C 人工降雨沖蝕試驗數據（第四章之試驗） 150 附錄D 第三章試驗數據與覆蓋率之關係（考慮重複試驗之變異） 152 附錄E 第四章試驗數據與覆蓋率之關係（考慮重複試驗之變異） 156 作者簡歷 1611652354 bytesapplication/pdfen-US土壤沖蝕紋溝間覆蓋率石塊降雨強度入滲soil erosioninterrillcover raterock fragmentrainfall intensityinfiltrationthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/55976/1/ntu-95-D87622002-1.pdf