目前台灣各地土壤流失量之估計,皆依據水土保持手冊(2005),但因近年來氣候變遷所造成之集中強降雨使得各項參數恐有變異。 為有效了解全台灣各地土壤沖蝕量,本研究利用143處試區之資料,依據相同土壤類別下,探討其沖蝕行為之規律性,故挑選出土壤性質(USDA)分類相同之土壤,依照該土壤所含有之試區數量多寡,一共挑出4種土壤類別(砂質壤土、坋質壤土、壤質砂土、壤土),共計39處試區進行深入探討及分析;研究中配合現地量測之沖蝕深度,計算土壤沖蝕量,並參照試區自然環境,運用USLE公式推估現地土壤沖蝕指數。 從各土壤質地的試區觀測,顯示由首次佈設到第1次量測的最佳時間,大約需要三個月到一年五個月。自第1次量測到結束量測,可獲得較佳試驗成果的量測時間大約八個月到一年五個月。
The amounts of soil loss in each district in Taiwan are based on the Soil Conservation Handbook (2005). Due to climate change and intensive rainfall in recent years, the parameters which are used in estimating soil erosion in the Handbook might change. In order to understand the amount of soil erosion around Taiwan, the study laid 143 tested areas of measuring soil erosion in order to investigate and build models. Regularities of erosion behavior of different soil categories are investigated. The research focuses on 39 areas of the 143 tested areas for further discuss and analysis based on four types of soils which are sandy loam, silty loam, loamy sand and loam in USDA classification. In order to calculate the volume of soil erosion, this research cooperates with the erosion depths measured in-situ, consults the natural environment of testing area, and then estimated soil erosion indices by using USLE formula. From observations on different soil textures, results show that the best timing for the first measurement between three to seventeen months after the test areas being set. The duration of observation from the first measurement needs eight to seventeen months to get a better result.