臺灣中部合歡山土壤碳長期累積速率之推估

The Estimation of Carbon Long-term Accumulation Rate for Soils on Hehuan Mountain in Central Taiwan

本研究在臺灣中部海拔在3,000m左右的高山地區，現代植被為高山箭竹林的環境下，採集兩個土壤剖面，初步探討自全新世以來，合歡山高山環境下土壤化育型態，並推估土壤碳儲量與長期土壤碳累積速率，及其與環境變遷之關聯性。研究成果顯示，合歡山兩個土壤剖面（HWS、HWM）各自有兩個層序，其碳儲量分別為35.44kg/m2和73.19kg/m2。最後本研究在HWM之2A層採集到碳樣本進行C14分析，並配合地層對比紀錄，土壤層序O～Bw1形成年代約在1,720B.P.，歷經溫暖潮濕氣候，其碳儲量累積速率為16.31（g/m2）/yr|土壤層序Bw1～2A形成年代約在1,720～3,370B.P.，歷經乾冷與溫暖氣候轉變期，其碳儲量累積速率為20.97(g/m2)/yr|土壤層序Bw2～2A形成年代約為2,590～3,370B.P.，歷經乾冷氣候，其累積的碳儲量約為31.09kg/m2|而3,370B.P.所累積碳儲量約為62.65kg/m2，平均累積速率為18.59(g/m2)/yr。
Two soil profiles were collected in the alpine region 3,000 meters above sea level in central Taiwan where the alpine niitakayamensis dominates the vegetation. This study estimates soil carbon storage and its long-term accumulation rate in this mountainous area as a basis for future correlation on paleoclimate. Field observation shows a bi-sequence along the soil profiles in the Hehuan Mountain area. A 14C dating was available from the charcoal found at the soil horizon of 2A of HWM. Additional soil ages were obtained from soil profiles nearby with similar characteristics of soil horizons and field morphologies published in literature. The results show the carbon storages of 35.44 kg/m2 and 73.19 kg/m2 for HWS and HWM, respectively. A rate of 16.31 (g/m2)/yr organic carbon is stored and accumulated in soil horizons of O to Bw1 since 1,720 BP when a warm and humid climate prevailed. A great rate of 20.97 (g/m2)/yr is suggested for the soil horizons of 2A to Bw1 developed from 3,370 to 1,720 BP. in the climatic transition from dry-cold to warm. The highest rate of 31.09 kg/m2 was found in soil horizons of 2A to Bw2 with their ages of 3,370~2,590 BP, when a cold climate dominated. These results give an overall estimation of 62.65 kg/m2 and 18.59 (g/m2)/yr for the carbon stock and its accumulation rate over the past ,370 years.