檳榔園水文特性之研究

Studies on Hydrological Characteristics of an Areca Palm Plantations

陸象豫(Shiang-Yue Lu) ； 黃良鑫(Liang-Shin Hwang) ； 傅鶴翹(Ho-Chiao Fu)

《台灣林業科學》 14卷2期 (1999/06) Pp. 211-221

https://doi.org/10.7075/TJFS.199906.0211

摘要

本文根據林試所蓮華池分所滲漏計試區試驗結果及鄰近檳榔園觀察所得，陳述檳榔性狀性，習性，並比較成齡檳榔園與草生地及杉木林地的水文特性。檳榔植株為單幹型，幹莖通直不分歧，6-9枚具蠟質羽狀複葉，聚生於幹頂，樹型固定而少有變化。截留容量約1.5mm，遠較其他林型為低；穿落雨佔降雨量的比率高出林冠空隙比率甚多，幹流量比率則可高達85%。根系為放射型不定走向鬚根，數量眾多且大多密佈於離樹幹基部約lm範圍內。入滲試驗顯示，試驗90min後的入滲速率約0.22cm/min，高於大多數降雨之強度，致雨水多能進入地表；惟進入土層內的水分多沿腐敗根係所產生的水流路徑以次地表逕流方式迅速流至下坡處，造成流量歷線呈驟起驟落狀，保存於土壞層的水分反而相對降低。在土壤水分充足時檳榔試區因蒸發散而消耗的水分估計約在6.5mm/d，較杉木及草生地試區為高；惟在乾旱情況下，檳榔的蒸發散損失與杉木林及草生地間之差異即不顯著。同一土壤深度下，檳榔試區地表月平均溫度較天然闊葉林高出1.3-3.6℃，幾乎與草生地或空曠地相差無幾；因此檳榔園之有機質會因溫度增高而加速分解，導致次地表逕流取樣水中Ca(上標 2+)，Mg(上標 2+)，N(上標 +)，SO(上標 2-)4，HCO(上標 -)3等土壤營養基含量較杉木及草生地試區為高，但是否會造成地力衰退尚無資料可證實。

關鍵字

檳榔 ； 滲漏計 ； 蒸發散量 ； 逕流歷線

並列摘要

In recent years the financial incentives for land owners have been favorable for the cultivation of areca palm (betel nut) on slopelands. Consequently, low- to mid-elevation forested slopelands have been cleared and cultivated on a large scale. The impacts of slopeland areca palm plantations on soil and water conservation are serious enough to have attracted much concern of government and many environmental groups. In order to provide basic information for management strategies and policy makers, we investigated the characteristics of areca palm and analyzed the hydrologic factors of a mature areca palm plantations by observations using a lysimeter and several plots in the Lienhuachih station of the Taiwan Forestry Research Institute. Areca palm has a single stem with no divergence and 6 to 9 coriaceous pinnate leaflets on the top. A tall and single-layer canopy produces a much higher percentage of throughfall of rainfall than do crevice areas in the whole canopy. The interception capacity was estimated to be about 1.5 mm, which is relatively low compared with that of other forest stands. In addition, stemflow can be observed with a small amount of rainfall, and a maximum proportion of 85% of total rainfall has been recorded as stemflow. A large number of fine roots that are mostly concentrated within 1 m from the base of the stem create a good pipe flow system once they decay. This extensive small channel system not only resulted in infiltration rates after 90 mm of as high as 0.22 cm/min on the areca palm plot, but also caused the peak of the storm hydrograph to occur immediately after the rainfall peak. The estimated evapotranspiration losses from areca palm plot were about 6.5 mm/d under wet soil conditions and were the highest of 3 plots of China fir, weeds, and areca palm, respectively. However, there was no significant difference among evapotranspiration losses of the 3 plots when soil was dry. The monthly average temperature of topsoil of the areca palm plot was 1.3-3.6℃ higher than that of China fir and natural hardwood plots. This indicates that rates of decomposition of organic matter will be higher than that of forested lands. The higher Ca(superscript 2+), Mg(superscript 2+), N(superscript +), SO(superscript 2-)4, and HCO(superscript -)3 concentrations in water samples from the areca palm plot support this viewpoint indirectly.

並列關鍵字

areca palm (or betel nut) ； lysimeter ； evapotranspiration ； hydrograph