以水泥圓球模擬石塊覆蓋方式對紋溝間土壤沖蝕之影響機制

The Effects of Rock Fragment Mulch Cover Simulated Using Mortar Ball on The Mechanism of Interrill Soil Erosion

羅穎頎(Ying-Chi Lo)

指導教授 ： 范正成

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01191

摘要

本研究的主要目的在於探討石塊覆蓋方式對紋溝間土壤沖蝕之影響機制。本研究之沖蝕試驗採用台北縣新店山區的黃壤土，並利用特別設計之試驗箱及人工降雨機進行試驗。試驗箱的坡度固定為20%。利用人造之水泥圓球鋪放在土壤表面作為試驗之覆蓋物，並改變其覆蓋率與覆蓋方式，於兩種強度的人工降雨下進行沖蝕試驗。覆蓋率分別為0%、10%、20%、30%、40%及50%等共六種；而覆蓋方式則採用全部露出土壤表面及部分嵌入土壤中兩種，其埋入率分別為0%與50%；降雨強度則分別為40mm/hr與90mm/hr。
試驗結果發現，有石塊覆蓋之試體，在低降雨強度且覆蓋率低於40%時可降低土壤表面之逕流率；石塊全部露出土壤表面時，對降低逕流沖蝕、飛濺沖蝕，及總沖蝕率之效果較石塊部分嵌入時理想，但在覆蓋率10%時對降低逕流沖蝕及總沖蝕率則是石塊部分嵌入時較好，但兩種覆蓋方式皆能有效降低沖蝕。對降低沖蝕效果而言，當石塊全部露出土壤表面、低降雨強度下且覆蓋率大於40%時效果最好。經迴歸分析結果發現，沖蝕量與覆蓋率、覆蓋物的埋入比率及降雨強度有不錯之關係。

關鍵字

土壤沖蝕 ； 紋溝間土壤沖蝕 ； 水泥石塊 ； 覆蓋率 ； 石塊覆蓋方式 ； 降雨強度

並列摘要

The main purpose of this study is to investigate the effects of rock fragments used as mulch cover on interrill soil erosion. The soil used in the soil erosion tests was collected from a mountainside at Sindian, Taipei County. Erosion Boxes and a rainfall simulator were specially designed and fabricated for this study. During the tests, the slope steepness of the erosion boxes was maintained at 20%. Mortar Balls were placed at the soil surface as the mulch cover. The rate and type of cover were changed, and two different rainfall intensities were simulated and applied in this study. The erosion tests were repeated on soil samples at the cover rates of 0%, 10%, 20%, 30%, 40% and 50% and types of completely exposed to the soil surface and partially embedded into the soil (i.e. the embedded ratio was 0% and 50%), and rainfall intensities of 40 and 90 mm/hr.
It was found from the test results that while the rainfall intensity was low and the cover rate was less than 40%, the runoff rate decreased. While the rock fragments were completely exposed to the soil surface, the runoff erosion, splash erosion and total erosion rate were found less compared to that while the rock fragments were partially embedded into the soil. At the cover rate of 10%, it was found that while the rock fragments were partially embedded into the soil, the runoff erosion and total erosion rate were found less. Nevertheless, both the two types of cover could effectively reduced the erosion. It was also found that while the rock fragments were completely exposed to the soil surface, the rainfall intensity was low and the cover rate was greater then 40%, the reducing effect of soil erosion was the best. After regression analysis, an equation was proposed to relate soil erosion, cover rate, embedded ratio and rainfall intensity. The relationship were found very satisfactory.

並列關鍵字

soil erosion ； interrill soil erosion ； mortar rock(ball) ； cover rate ； rock cover type ； rainfall intensity

參考文獻

1. 山坡地土壤調查報告－臺北縣、基隆市暨臺北市(1986)，臺灣省政府農林廳山地農牧局編印。

2. 范正成、謝宏元(1991)，「田間人工降雨機之回顧、研究及比較」，中華水土保持學報，22(1)：pp.9-20。

3. 范正成(1993)，「臺灣地區土壤沖蝕預測公式之回顧、研究與展望」，中華水土保持學報，24(2)：pp.131－152。

7. 吳嘉俊(1998)，「礫石地之地表敷蓋次因子」，中華水土保持學報，29(4)：pp.351-365。

9. 楊文仁、范正成(2003)，「運用類神經網路建立紋溝間土壤沖蝕推估模式之研究」，中華水土保持學報，34(3)：pp. 271-279。