塔塔加地區三種林型土壤腐植酸之特性

Character of Soil Humic Acids at Three Forest Types in Ta-Ta-Chia Area.

葉旭容(Hsun-Jung Yeh)

指導教授 ： 王亞男

共同指導教授 ： 王明光(Ming-Kuang Wang)

國立臺灣大學/生物資源暨農學院/森林環境暨資源學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01637

摘要

不同植生條件下生成的土壤有機質組成成份仍舊不清楚。本研究目的在了解不同植生條件下，土壤腐植酸之特性差異。本研究選取塔塔加地區（Taiwan Long-Term Ecological Research, LTER）臺灣二葉松（Pinus taiwanensis Hay., Taiwan red pine, TP）、臺灣鐵杉（Tsuga chinensis var. formosana Li & Keng, Taiwan hemlock, TH）及玉山箭竹（Yushania niitakayamensis (Hay.) Keng f., Yushan cane, YC）三種不同林型下土壤進行研究，比較其土壤物理化學基本性質、土壤有機質及腐植酸等組成差異，結果顯示三種土壤酸鹼值（pH）介於 3 ~ 4 之間為強酸性土壤，由於酸性森林土壤及強烈淋洗作用造成可交換性鹽基陽離子含量極低，而土壤有機碳含量趨勢：臺灣鐵杉＞臺灣二葉松＞玉山箭竹。固態13C-NMR分析結果指出不同樹種新鮮植體（鮮根、嫩枝、鮮葉）有機官能基相對百分比含量不同，三種樹種均以纖維素、半纖維素為主要成分，但是，臺灣二葉松及臺灣鐵杉含較多的木質素，而玉山箭竹較少，有機官能基含量趨勢為：O-alkyl-C> alkyl-C> N-alkyl-C> acetal-C> aromatic-C> phenolic-C≈ carboxyl-C。臺灣二葉松及臺灣鐵杉Oa層纖維素及半纖維素相對含量高於玉山箭竹，在高山森林土壤裡臺灣鐵杉林型下的土壤有機質不易分解，三種林型下植體分解難易程度為（由易至難）：玉山箭竹＞臺灣二葉松＞臺灣鐵杉。由元素分析得知臺灣二葉松及臺灣鐵杉HA具有較高的H/C值及O/C值。反之，玉山箭竹土壤有機質容易分解，玉山箭竹HA之H/C值及O/C值較低。FTIR分析結果指出不同林型下腐植酸（humic acids, HAs）有機官能基組成相對百分比含量不同，但都含有脂肪族、芳香族及多醣類結構。另外，在有機官能基相對含量趨勢上，臺灣二葉松及臺灣鐵杉均為：alkyl-C> O-aklyl-C≈ N-alkyl-C> aromatic-C> carboxyl-C> acetal-C> phenolic-C。玉山箭竹為：alkyl-C> aromatic-C> O-aklyl-C≈ N-alkyl-C> carboxyl-C> acetal-C> phenolic-C。本研究認為三種林型下土壤有機質分解難易程度（由易至難）：玉山箭竹＞臺灣二葉松＞臺灣鐵杉。

關鍵字

腐植酸 ； 土壤有機質 ； 植生 ； 13C-NMR

並列摘要

Compositions of soil organic matter developed form various vegetations remain unclear. The aims of this study were to investigate the different characteristics of humic acid from various vegetations in temperate rain forest, Ta-Ta-Chia, central Taiwan. Three forest types were selected for this study, such as Taiwan red pine (Pinus taiwanensis Hay., Taiwan red pine, TP), Taiwan hemlock (Tsuga chinensis var. formosana Li & Keng, Taiwan hemlock, TH), and Yushan cane (Yushania niitakayamensis (Hay.) Keng f., Yushan cane, YC). The soil physical and chemical properties, soil organic matters, and humic acid constituents were characterized. Soil pH ranged from 3 to 4. Low exchangeable cations caused by acidic and intense leaching of forest soils. Total organic carbon contents showed the trend as: TH > TP> YC. From CP/MAS 13C soild-state NMR analyses, the constituents of organic functional groups showed the various with respect to different plants and tissues, including fresh twigs, leaves and roots. Cellulose and semi-cellulose are the major components of plant tissues. However, the TP and TH comprise more lignin than that of YC. The contents of different functional groups in plant tissues showed the trends as follows: O-alkyl-C > alkyl-C >N-alkyl-C > acetal-C > aromatic-C > phenolic-C ≈ carboxyl-C. The Oa horizon in TP and TH contain more cellulose and semi-cellulose than that of the YC. The debris of Taiwan hemlock forest type is not that easy decompose under the alpine forest soil environments. The decomposition rate of plant tissues of three forest types showed the trends: YC > TP > TH. From elemental analyses, the humic acids fractionated from the TH and TP forest types soils contain more H/C and O/C atomic ratios (i.e., aliphatic carbon) than that of YC forest type, indicating the slow decomposition of TH and TP plant tissues. On the other hand, the YC showed low H/C and O/C atomic ratios, indicating easier decompose of YC plant tissues. From Fourier Infrared (FTIR) spectrometry analyses, the humic acids showed different aliphatic, aromatic and polysaccharide contents. From CP/MAS 13C soild-state NMR analyses of soil humic acids, the TH and TP contain more residual cellulose and semi-cellulose contents than that of YC forest types due to slow decomposition rate. The semi-quantitative of organic functional groups of the TH and TP showed the following trends: alkyl-C > O-alkyl-C ≈ N-alkyl-C > aromatic-C > carboxyl-C > acetal-C > phenolic-C, however, the YC humic acids showed the different trends: alkyl-C > aromatic-C > O-alkyl-C ≈ N-alkyl-C > carboxyl-C > acetal-C > phenolic-C. In general, we suggest that the degree of debris decomposition in three forest types are YC > TP > TH.

並列關鍵字

humic acid ； soil organic matter ； vegetation ； 13C-NMR

參考文獻

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