本研究探討森林坡面土壤水分時間、空間變化的特性，選定福山1 號試驗集水區右
側坡面試區，設置兩套時域反射儀(Time-Domain Reflectometry, TDR)土壤水分觀測系
統，長期監測土壤體積含水率變化。TDR 探針測定深度為0~15 cm、15~30 cm、30~45 cm、
45~60 cm、60~90 cm。研究期間土壤體積含水率時系列資料分析結果，在測定深度0~30
cm 範圍內，隨降雨條件而呈現明顯的變化，深度30 cm 以下則變化不明顯。從土壤水
分的變化趨勢來看，2003 年8 月和2004 年7 月期間因降雨量偏低，土壤體積含水率降
到最低點，在2003 年10 月、12 月，和2004 年2 月、4 月等月份，出現15 日以上無降
雨，淺層土壤體積含水率亦呈現明顯的降低的情形。其次，採取直徑20 cm、長度40~50
cm 之大型不擾動土壤試體，進行飽和、不飽和水力傳導度測定。由八個試體變水頭飽
和水力傳導度試驗結果，飽和水力傳導度主要在0.8∼10.9×10-3 cm/sec 之間，測定值隨
試體的深度增加而遞減。經變異數分析結果，八個試體、以及不同深度之間呈顯著差異。
以噴灑供水方式調定不同降雨強度條件，測定不飽和水力傳導度，在試驗初期降雨強度
約6mm/hr 的條件下，由於土壤大孔隙中陷入空氣，使深度10 cm 的水力傳導度最低，
隨降雨強度增加大孔隙中水分移動，促使水力傳導度遞增，而深度30 cm 在降雨強度大
於18mm/hr 時出現壓力水頭為正之達到飽和的情形。綜合上述結果，集水區土壤水分通
量主要發生在深度30 cm 以內，由於深度30cm 以下為難透水層，當坡面土壤達到飽和
時，將發生坡面側向流。This study is to investigate the properties of soil water spatial and temporal variation on
forest slope. Two set of Time-domain reflectometry (TDR) were installed on the right slope of
the Fushan No. 1 experimental watershed, that in order to continuously record the volumetric
soil water content. The five measuring depth of probe are 0-15 cm, 15-30 cm, 30-45 cm,
45-60 cm, and 60-90 cm. According to the analysis of time series soil volumetric water
content data, the data of 0~30cm soil depth varied evidently in the condition of rain occurred,
but varied less in the soil depth of more than 30cm.In research period, rainfall of August 2003
and July 2004 were lower than other months, the soil water content was lowest. Also, it
appears that soil water content was little when above 15 days was no rainfall occurred in other
months.
Besides, eight undisturbed soil samples with 20 cm diameter and 40~50 cm length were
gotten to measure saturated and unsaturated hydraulic conductivity. The saturated hydraulic
conductivity of soil samples by falling head test were about 0.8~10.9×10-3 cm/sec, and the
measured value of different soil depth decreased with the increasing depth. From the result of
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analysis of variance, there is a significant difference in eight samples and three depths at the
5% level. Also, in the condition of artificial rainfall intensity about 6 mm/h by sprinkle, the
unsaturated hydraulic conductivity of 10 cm soil depth was smaller because of air impeded to
soil macropore in early time, and the value increase when the rainfall intensity increase.
However, the hydraulic conductivity of beneath 30 cm depth was close to saturation in the
rainfall intensity about 18 mm/h. According to the mentioned results, the soil water flux
mainly occurred in 30 cm depth range. The saturated lateral flow predictably occurred on 30
cm depth with lower impermeable layer in situation of rainfall intensity exceed 18 mm/hr
