墾丁地區階地土壤類型與碳儲量之初估

Classifications of the soils of terraces in Kenting Peninsula and their preliminary estimations for soil carbon stocks

本研究在墾丁地區採取6個代表性土壤樣本，探討土壤的化育特徵、作用與分類，並進而推估各土壤表層的土壤碳儲量。結果顯示，土壤化育特徵與化育程度隨地形面年代增加而增高，較高位土壤呈現輕度磚紅壤化。按照美國土壤分類系統，化育程度低的KT-5、KT-4和KT-3a（0-200cm）為新成土（Entisols），化育程度較高的土壤為極育土（Ultisols）。各土壤間除了KT-2和KT-3b表層土壤碳儲量較高，其餘土壤的表層碳儲量均偏低（<4 kg/m2），各表層土壤之碳儲量，與土壤構造、理化性質等均無明顯的關聯性。另比較台灣其他地區的土壤碳儲量推估之研究，發現各地土壤表土的碳儲量和土壤類型、植被、降水量等並無明顯之關聯性，而與氣溫因子之間具較明顯的負相關性，兩者的相關係數約0.7 (p<0.05)，不過土壤表層碳儲量與氣溫之間的因果關聯性，仍需進一步的調查研究來證實。

Six soils were sampled in the Kenting area to reveal pedogenic characteristics, processes and classification, as well as to estimate the soil organic carbon stocks. The pedogenic morphologies and physicochemical properties indicated that the developmental degrees of the soils increase with age. However, the older soils showed weak lateralization based on the Alt, Fet, and Sit ratios. Three soils, KT-5, KT-4, and KT-3a (0-200cm), could be classified as Entisols, whereas the other soils were classified as Ultisols according to the Soil Taxonomy. The topsoils (0-30 cm) of the KT-2 and KT-3b had high amounts of soil carbon stocks, but carbon stocks on the other soils were less than 4 kg/m2. Soil carbon stocks of the topsoils for each soil showed no evident relationship with soil structures and physicochemical properties. We further reviewed several soil carbon stock studies. Soil carbon stocks of the topsoils within varied ecosystems in Taiwan were not related to vegetation, soil types, and precipitations but related to mean annual temperatures, of which the correlation coefficient of the latter is about 0.7.