臺灣中部林地斥水土層之研究

WATER REPELLENT LAYERS OF FOREST SOILS IN CENTRAL TAIWAN

林昭遠(Chao-Yuan Lin) ； 陳明義(Ming-Yih Chen) ； 謝顯宗(Shean-Tzong Hsieh)

《中華水土保持學報》 25卷2期 (1994/06) Pp. 73-81

https://doi.org/10.29417/JCSWC.199406_25(2).0002

摘要

本研究測定臺灣中部不同植群生育地之飽和入滲率以及土壤與枯枝業層的斥水強度，藉以探究斥水土層形成的機制。並以玉山國家公園火燒跡地爲例，探討林地火燒後斥水土層對植群入侵與水土流失之影響。林地斥水土層主要分布於表土層，植群種類及微生物活動影響疏水物質之運移。干擾較大的農耕地或道路邊坡，土壤中的疏水物質不易累積，土層無斥水跡象。闊葉樹之枯枝葉易被分解，產生之疏水物質易深入土層，斥水性強；唯山區多石質土，土壤粗孔隙多，疏水物質影響林地之入滲率不明顯。高山草生地根系密結且表土斥水，入滲量少，水源涵養能力低。臺灣二葉松之枯枝葉不易分解，多量累積易繁生眞菌，形成大片斥水菌絲層，增加林地火燒危險度。木麻黃防風林帶多旱季多量落葉，爲眞菌提供豐裕之基質，易產生斥水土層，抑制水分或養分深入根圈，此對其生育不利，火燒尤易發生。玉山國家公園箭竹林火燒跡地嚴重斥水，有礙入侵種子發芽。在斥水與陡坡情況下，表土雖有大量片岩與存活箭竹根系之保護，土壤流失量不大，但灰分中之養分易被地表逕流水沖失，此影響植物自然入侵及人工復育。

關鍵字

斥水土層 ； 疏水物質 ； 入滲率 ； 林火

並列摘要

The saturated infiltration rates of the major forest soils in central Taiwan were measured. The hydrophobic potentials of forest soils and litter extract were analyzed for unfolding the mechanism of water repellent layer (WRL) formation. A burned site at Yushan National Park was used to investigate the effects of WRL on plant invasion and soil erosion after fire. WRL is mostly distributed at top soils. Vegetation types and microbial activities affect the hydrophobic potential and distribution of WRL. No WRL was observed at upstream farming areas and/or roadside slopelands, because the hydrophobic substances were easily decomposed under frequent disturbances. Litters of hardwood forest are more readily to be decomposed. The hydrophobic potential of undisturbed hardwood stand is usually high, but the effect of hydrophobic substance on soil infiltration is not obvious due to macro porosity in rocky sites. Dense root systems and hydrophobic substances cause low soil infiltration rate in alpine grasslands. Taiwan red pine forest usually accumulate more litter and result in highly hydrophobic and flammable litter layers owing to mat formation and stimulated growth of some fungi. WRL inhibited the germination of invaded seeds and the soil infiltration rate at the burned site of Yushan National Park. Owing to the steepness and surface runoff, ashes and nutrients were easily to be eroded. Therefore, the natural regeneration or artificial rehabilitation were retarded.

並列關鍵字

Water Repellent Layer (WRL) ； Hydrophobic Substance ； Infiltration Rate ； Forest Fire