香楠林坡面土壤水分空間變化之研究

Spatial Varieties of Soil Moisture in Machilus zuihoensis Hillslope

李錦育(Chin-Yu Lee) ； 林永隆(Yung-Lung Lin)

《中華水土保持學報》 33卷1期 (2002/03) Pp. 69-78

https://doi.org/10.29417/JCSWC.200203_33(1).0008

摘要

森林爲台灣重要的資源之一，而集水區內生長良好的森林型態，具良好的水土保育功能，林木的樹冠截留、地表植群及腐植質的被覆等，均具有降低地表逕流、增加土層厚度及涵養水源等功效，而水分於地表的入滲及土壤中的移動與上述密切相關，因此，爲瞭解降雨對土壤水分時空的變化，本研究於香楠林集水區選擇不同林地覆蓋之坡面埋設各深度之土壤水分張力計（Watermark），探討不同地況及空間下對土壤水分的變化及其影響；利用入滲計（Guelph Permeameter）於各深度下施作入滲試驗，以瞭解不同深度下之土壤理化性質對入滲率之影響。經初步試驗結果得知：受土壤質地及植生覆蓋情況等的影響，三區土壤水分變動大小爲：雜木林區＞香楠林區＞裸露區；另外，在乾季或濕季及短延時條件下，淺層土壤之水分變動均較大，且隨著深度增加而趨於緩和。

關鍵字

土壤水分 ； 葉面積指數 ； 入滲率

並列摘要

The forest is one of the most important resources in Taiwan. A well-vegetated forest in the watershed can conservation. Good tree-crown interception, dense surface vegetation and high humus content can decrease surface runoff, increase soil layer depth and conserve water in soil. These effects are closely related with infiltration rate on ground surface and underground water movement. To understand the time and spatial variance of soil moisture, tensiometers (Watermark), have been set up to measure rainfall intensity, rainfall duration and antecedent moisture condition. In addition, infiltrometer (Guelph Permeameter) has been used to perform infiltration experiments at different depth to shed light on the influence of physical and chemical characteristics of soil on infiltration rate and the correlation between infiltration rate and soil water variance. According to the preliminary experiment results, the soil water variances in three areas in sequence are: miscellaneous forest area＞ Machilus zuihoensis area＞bare area. Moreover, the water content of thin layer soil has more variance during dry and/or wet season or short rainfall duration condition, and the variance tends to decrease with increasing depth.

並列關鍵字

soil moisture ； leaf area index (LAI) ； infiltration rate