嘉義祝山地區砂質與壤質淋澱土土壤之特性與化育作用

• Main Authors: 邱春媚, Chiu, Chun-Mei
• Other Authors: 陳尊賢, 臺灣大學：農業化學研究所
• Format: Thesis
• Language: Chinese; English
• Published: 2004
• Subjects: 淋澱土; 淋澱化作用; 土壤微形態構造; 黏土礦物; 風化序列; 化育作用; Spodosols; podzolization; clay illuviation; soil micromorphological characteristics; Peacock; Arctic
• Online Access: http://ntur.lib.ntu.edu.tw/handle/246246/58465; http://ntur.lib.ntu.edu.tw/bitstream/246246/58465/1/ntu-93-R91623410-1.pdf

淋澱土通常生成於冷涼潮濕的氣候、針葉林植生與砂質地母質。阿里山祝山地區位於台灣中部次亞高山地區，海拔高度約2,300公尺，年雨量3,910公釐，氣候終年涼爽濕潤、全年幾乎無明顯乾燥季節，此土壤溫度境況為溫和與土壤水分境況為濕潤。本研究區之植被為紅檜(Chamaecyparis formosensis)及鐵杉(Tsuga chinensis)佔優勢，並有少數華山松(Pinus armandii)或雲葉(Trochodendron aralioides)相伴而生，人工柳杉林，亦為本區主要林相。地被植物主要以玉山箭竹(Yushania niitakayanensis)佔絕對優勢與芒草(Miscanthus floridulus)和一些蕨類及苔蘚類植物。研究區屬阿里山山脈主脈上，為晚期中新世岩層，主要以砂岩、坋砂岩與頁岩所構成，大部分母質化育生成之淋澱土為黏質壤土的。本研究目的在探討嘉義祝山地區砂質與壤質淋澱土土壤樣體之形態特徵、理化性質、黏土礦物組成、土壤之化育作用與礦物風化序列。 沿祝山地區林業道路兩旁至祝山頂間採集五個代表性土壤樣體。研究顯示五個供試土壤樣體，一個屬於壤質砂土，三個屬於砂質壤土，一個屬於砂質黏壤土，均屬於強酸性土壤(pH 3.2-5.0)，且極低交換性鹽基與極低鹽基飽和度(BS<15%)之土壤化學性質。有機碳的分佈，主要分布在土壤表層之O或A化育層有最大量，淋澱層(Bs)次之，漂白層(E)含量最低。在土壤物理分析上，粘粒含量在漂白層通常較低，隨深度增加而增加，在B化育層達到最大量，而C層又漸減。淋澱化作用盛行時，土壤剖面中亦可發現粘粒有向下移動聚積(Bt)之現象且在淋澱層中進行累積。 淋澱層中之有機碳含量與無定形、有機態以及游離態鐵與鋁含量均明顯較漂白層(E)高，顯示土壤中有多量活性鐵、鋁與有機質形成有機鐵或鋁錯合物型態向下移動聚積，進而形成暗色或紅棕色等淋澱化物質之淋澱土。黏粒與有機碳含量以及鐵、鋁之線性迴歸分析顯示，本區不論砂質或壤質淋澱土中，淋澱化物質之化育作用，除了與有機碳含量有顯著相關之外，另與粘粒移動亦有顯著相關。 由土壤微形態構造觀察發現，暗黑色有機錯合物沿著孔隙藉由溶質移動而向下移動。在適當環境下，土壤孔隙或土壤砂粒子與土壤基質上沉澱而生成有機之披覆體或有機鐵與鋁之披覆體。除暗色有機錯合物之外，同時可觀察到細微粘粒膜之存在，此與土壤物理分析與化學分析結果吻合，意即有機物與鐵、鋁以及粘粒移動是可能同時存在於土壤體中。五個土壤樣體之黏土礦物組成，在漂白層(E)中主要以蛭石、伊萊石及蛭石－伊萊石混層礦物為主，在淋澱層(Bs)中主要以蛭石含量較豐，且亦有相當量之蛭石－伊萊石混層礦物，同時水合蛭石含量也漸增。母質則以伊萊石為主，推測本研究區內礦物風化序列為伊萊石→蛭石(或蛭石－伊萊石混層礦物)→水化蛭石。 本研究區之砂質與壤質淋澱土之土壤化育作用可能同時具有淋澱化作用與粘粒移動作用。在坡度平緩、質地屬壤質砂土或砂質壤土且腐植質含量較豐以及有機酸含量充分情況下，有機物與鐵或鋁鍵結含量多，伴隨大量溶質滲漏而較易移動，以淋澱化作用為主伴隨些微黏粒移動，但在砂質黏壤土之地區，其粘粒聚積作用與淋澱化作用同時存在。 Spodosols occur mainly in cool humid climates under coniferous forest vegetation in medium to coarse textured parent material. Chushan area of Alishan is located in subalpine area in southern Taiwan. The elevation of study area is about 2,300 meters. Annual rainfall is 3,910 mm. The climate is cool and humid and has no dry season. The soil temperature regime and soil moisture regime are mesic and udic, respectively. The vegetation types are dominant with Taiwan red cypress (Chamaecyparis formosensis) and Chinese hemlock (Tsuga chinensis), with minor amounts of pine (Pinus armandii) and Wheel stamen tree (Trochodendron aralioides). Peacock pine (Cryptomeria japonica) which is planted by human also takes one important part of vegetation types. The ground vegetation is dominated by Yushan cane (Yushania niitakayanensis), with minor amounts of Japanese silvergrass (Miscanthus floridulus), fern and moss. The study area is located at Alishan mountain, which was mainly formed by late Miocene sandstone, siltstone and shale. The soil texture of the parent material of Spodosol in the study area is clay loam. The objectives of this study are to explore the soil characteristics, physical and chemical properties, compositions of clay minerals, genesis and weathering sequence of clay mineralogy of sandy and loamy Spodosols in Chushan region in Chiayi. Five representative soil pedons were sampled at the top of Chushan. The soil texture of spodic horizon in five pedons can be divided into three classes including loamy sand, sandy loam, and sandy clay loam. Soil Chemical properties are characterized with strong acidity (pH 3.2-5.0) and very low bases saturation (<15%). The depth distribution of organic carbon is characterized by higher content in the spodic horizon (Bs) than that of overlying eluvial E horizon. Clay was significantly reduced in albic E horizon and increased in the spodic horizon of pedons. Podzolization is regarded as the main pedogenic process combined with minor process of clay illuviation occurred in the pedons of Chushan area. The content of organic carbon and different forms of Fe of the spodic horizon are significantly higher than that of albic horizon. These results indicate that the spodic horizon is formed predominantly by the illuviation of organo-metallic complexes. The significant correlations among clay, organic carbon, and Fe content were found by the linear regression analysis (p<0.001). These relationships indicate that the podzolization is main pedogenic process for sandy and loamy Spodosols in the study area. The soil micromorphological characteristics suggest dark pellets of organic compounds were leached downward with soil solution along the soil pores during the wet season. The organs or organo-ferrans coated along the soil voids, grains, and soil groundmass in soil horizons. Meanwhile, the slightly oriented clay coating along the soil pore can be found. The soil physical and chemical properties also indicated that the organic carbon, Fe, and clay were illuviated in the spodic horizon. The clay mineralogy of albic horizon in five pedons are prominent with vermiculite, illite and vermiculite-illite interstratified minerals, but those in the spodic horizon is major with vermiculite and hydroxy-interlayered vermiculite (HIV). The clay mineralogy of parent material in five pedons is major with illite. The weathering sequences of clay minerals in five selected pedons can be proposed as the following sequences: illite → vermiculite, vermiculite and illite interstratified minerals → vermiculite or HIV. Podzolization and clay illuviation are the pedogenic processes of sandy and loamy Spodosols in the study area. Forest soils located in gentle slope are characterized by loamy sand or sandy loam texture, abundant humus and organic acid, more content of organo-Fe complexes. Podzolization is the main pedogenic process in sandy Spodosol, however, the podzolizaiton and clay illuviation could be existed at the same time in loamy Spodosols. 中文摘要 --- Ⅰ 英文摘要 --- Ⅲ 目錄 --- Ⅴ 表目錄 --- Ⅶ 圖目錄 --- Ⅷ 第一章 前言 --- 1 第二章 前人研究 --- 3 第三章 材料與方法 --- 10 第四章 結果 --- 27 第五章 討論 --- 102 第六章 結論 --- 116 第七章 參考文獻 --- 118 附錄 --- 125