蓮華池試驗林不同土地利用的土壤孔隙率特性及其水資源涵養能力研究

Study on the Soil Porosity Characteristics and Water Resource Conservation Capacity of Various Land Use in the Lienhuachih Experimental Forest

曾俊偉(Chun-Wei Tseng) ； 陳明杰(Ming-Chieh Chen)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 32卷1期 (2018/03) Pp. 23-36

https://doi.org/10.6542/EFNTU.2018.32(1).3

摘要

土壤孔隙為涵養水資源的場所，不同土地利用會影響土壤孔隙特性，藉由土壤孔隙率的調查，亦可瞭解不同土地利用對水資源涵養能力的差異。本研究選取蓮華池試驗林的天然林等10種不同土地利用試區，每一個試區選取6個取樣位置，每個取樣位置採取深度為0-10 cm、10-20 cm、20-30 cm的不擾動土壤樣本，進行乾總體密度及孔隙率率等土壤物理性質分析。結果顯示，將土地利用區分為林業使用、農業使用及非農業使用等3大類，土壤總孔隙率、大孔隙率、粗孔隙率等均呈現林業使用類型為最大值。雙因子變異數分析結果，在不同土地利用間、不同取樣深度間的總孔隙率、大孔隙率、及粗孔隙率等皆呈現顯著差異。總孔隙率與總體乾密度線性迴歸分析結果，10種不同土地利用試區皆呈現顯著負相關，亦即土壤顆粒容積率越高則總孔隙率越低；而大孔隙率可能受土壤團粒化、生物活動、植物細根形成的孔道等因素影響，僅檳榔園及桂竹林兩個試區的大孔隙率與乾總體密度呈現顯著負相關。其次，以土壤取樣深度30 cm的平均粗孔隙率計算一場降雨之水資源涵養能力最大值，其中，試區10（旱田）因非屬原始土壤狀況不予以討論，結果以試3區1（天然林）430.30 m^3 /ha為最佳，天然林的水資源涵養能力高於其他土地利用試區約100-250 m^3/ha。

關鍵字

土地利用 ； 土壤孔隙率 ； 水資源涵養 ； 蓮華池試驗林

並列摘要

Soil pores is essential to water conservation. Various land uses will affect characteristics of soil pores. Therefore, investigating soil porosity could find out differences in water resource capacity due to land uses. In this study, ten different land use plots were selected in the Lienhuachih experimental forest. Six locations were sampled in each plot with soil sampled at three depths of 0-10 cm, 10-20 cm and 20-30 cm in each location by undisturbed soil extraction method. The soil samples were used to analyze soil physical properties, which included dry bulk density and porosity etc. Ten various land use plots could be roughly divided into three categories: forestry use, agricultural use, and non-agricultural use. The results showed that soil total porosity, macroporosity, and coarse porosity of forestry use were the highest among the three categories. From two-way ANOVA, the difference of soil total porosity, macroporosity and coarse porosity between land use plots and between sampling depth were significant. Secondly, the total porosity and dry bulk density was significantly negatively correlated in each plot that suggests higher dry bulk density is associated with lower total porosity. However, macroporosity was probably affected by soil aggregation, biological activity, pipe structured formed by plant fine root, and other factors, that and dry bulk density was significantly negatively correlated merely in two land use plots of Makino bamboo and Areca nut. Meanwhile, maximum water conservation capacity of a rainfall event was estimated by the average coarse porosity of soil sampling depth range of 0-30 cm. Among the ten land use plots, other than plot no. 10 (dry land) belonging to non-original soil condition, maximum water conservation capacity of plot no. 1 (natural forest) was 430.30 m^3 /ha, which was higher than other land use plots with a range of 100-250 m^3/ha.

並列關鍵字

Land use ； Lienhuachih experimental forest ； Soil porosity ； Water resource conservation.