土壤有機碳為影響全球碳吸存及全球變遷的重要因子。本研究利用農業試驗所土壤資料庫網站的土系資料,以及地理資訊系統的空間內差方法,求得臺灣土壤有機碳的總量及空間分布,再與臺灣的地形、海拔高度、雨量、溫度等資料圖資套疊分析,探討這些因子與土壤有機碳之間的關係。在估算臺灣地區土壤有機碳的密度及貯存量上,表土0~30cm、0~50cm及0~100cm深度之有機碳密度介於1.93~16.95 kg/m2、2.48~26.17 kg/m2及2.49~46.09 kg/m2,平均值分別為8.77 kg/m2、11.45 kg/m2、14.95 kg/m2,儲存量分別為315 Tg、411Tg、537Tg。土壤有機碳密度與年平均溫度成反比,與雨量、坡度、海拔及年平均雨量成正相關,相關係數約為0.4。土壤有機碳密度與坡向相關係數低,以西向及西南向的SOC最低,東南方位的土壤有機碳最高。海拔亦會影響雨量、坡度、溫度及植生狀態,故海拔為影響土壤有機碳的主要因子。海拔高於500m、坡度>15%、年雨量高於2500mm及年均溫低於20℃,其土壤有機碳密度較高。
Soil organic carbon (SOC) plays a key role in the global carbon cycle and global change. In this study, we used statistical and geostatisticalmethods toobtain the relation of the spatial heterogeneity of SOC in Taiwan, and to investigatethe factors that influence it, such as topography, altitude,precipitation, and temperature. Our study was based on 14715 soil order samples obtained SOC storage and spatial distribution in Taiwan. The spatial variables of SOC were studied, using geographic information systems (GIS) and geostatistics.This paper explored a GIS-based approach for quantifying and mapping the values of SOC in Taiwan.Interpolated values of SOCdensity and stocks for the depth of30cm, 50cm,100 cmof soil layer, obtained by kriging based on a spherical model, ranged between 1.93 - 16.95 kg C m-2,2.48 - 26.17 kg C m-2,2.49 - 46.09 kg C m-2,respectivelyand the meanvaluewere8.77 kg Cm-2,11.45kg Cm-2,14.95 kg Cm-2,respectively;SOC stocks were estimated to be 315 Tg, 411Tg, and 537Tg,respectively.The correlationsof SOC densities betweenelevation, slope,andprecipitationshowed to be positive(r =0.456, 0.521, 0.458, respectively) but negative in temperature (r =-0.396)for the depth of 30cmof soil layer. The soil layer was deeper, the relationship was lower. The west and southwest aspect SOC density was the lowest but the southeast was highest.The elevation was the most important factorSOC density because it mightaffect precipitation, slope, temperature, and vegetation type.The SOC density was higher while the elevation> 500m, slope> 15%, annual precipitation> 2500mm, and average temperature <20℃.