鑒於臺灣目前所參考之土壤沖蝕性指數乃於30餘年前建立，距今已久遠，加上近年來，氣候變遷引起諸多嚴重坡地災害，同時，近年山坡地過度開發且土地利用變化差異甚大，顯示土壤沖蝕指數(soil erodibility, K factor)極具有重新建立與評估之必要性。本研究主要於臺南市、高雄市及屏東縣山坡地範圍內(100 m-1000 m)，於各縣市選取最具代表性之25個基標土系(benchmark soil series)，建立該地區K值之數值與繪製空間等值分佈圖。本研究採Wischmeieret al. (1978)公式計算各縣市山坡地基標土系之K值，並以克利金推估模式(Kriging interpolationmodel)繪製空間分布等值圖，以提供水土保持相關從業人員之參考。本研究結果顯示，台南市山坡地K值為0.010-0.073 t•ha•yr•ha-1•MJ-1•mm-1，高雄市山坡地K值為0.021-0.082 t•ha•yr•ha-1•MJ-1•mm-1，而屏東縣山坡地K值為0.0076-0.050 t•ha•yr•ha-1•MJ-1•mm-1，結果指出以高雄市山坡地土壤沖蝕潛勢較高。本研究調查之K值分佈與萬鑫森與黃俊義(1989)之K值分佈具有顯著差異，以台南市南化地區及高雄市荖濃溪上游甲仙區及六龜區之差異最顯著，K值由1989年的0.025增加至2016年的大於0.050，推測坡地受災害嚴重擾動與土地開發之影響所致。

Soil erodibility factor (the K factor) should be re-established due to soil properties have been probably obviously influenced by climate change and over developed of slopelands in recent years in Taiwan. The old K factor developed by Wann and Huang (1989) used in Taiwan might not be suitable longer because it has already established thirty years at least. This study selected 25 benchmark soil series in sloplands (100 m- 1000 m) for each city (Tainan, Kaohsiung and Pingtung) in southern Taiwan to analyze surface soil properties and calculated the K factors (based on Wischmeier et al. (1978)) and its spatial distribution. The results revealed that the K factors were 0.010-0.073 t•ha•yr•ha-1•MJ-1•mm-1 in Tainan, 0.021-0.082 t•ha•yr•ha-1•MJ-1•mm-1 in Kaohsiung and 0.0076-0.050 t•ha•yr•ha-1•MJ-1•mm-1 in Pingtung. Higher soil erodibility was found in the slopelands in Kaohsiung. Comparing with the results from Wann and Huang (1989), new K factors obviously increased by 2 times at Nanhua district in Tainan, and at districts of Jiaxian and Liugui in Kaohsiung, which might be attributed to serious disturbance of soils by violent climate or long-term change processes of land uses.