广西森林土壤有机碳储量估算及空间格局特征

Estimation and distribution patterns of organic carbon stock in forest soil in Guangxi

准确估算森林土壤有机碳库,研究其空间格局特征是陆地碳循环研究的关键与热点。利用森林资源连续清查样地资料,结合土壤剖面实测数据,估算广西森林土壤有机碳蓄积,分析不同经度、纬度、海拔的土壤有机碳密度的分布特征。研究结果表明:广西森林土壤有机碳1 852.5 Tg,其中红壤和赤红壤土壤碳约占76.1%,是土壤有机碳储量的重要组成部分。广西森林土壤碳密度为12.13 kg/m2,碳密度低于全国平均水平,地带性土壤有机碳密度大小顺序为黄壤>红壤>赤红壤>砖红壤。森林土壤有机碳密度的空间分布总体上有北部高于南部、四周高于中部的规律。从三向地带性上看,碳密度均呈现出高—低—高的"U型"分布,有机碳密度低值区域主要是受岩溶地区的影响。

The forest soil organic carbon stock estimation and its distributing patterns analysis is a research focus in terrestrial carbon cycle field. The forest continuous inventory plots data was used to estimate the forest soil organic carbon accumulation combined with the measured soil profile data in Guangxi. The soil organic carbon distribution characteristics in the different longitude, latitude, and altitude was analyzed. The results showed that： ① The forest soil organic carbon content was 1 852. 5 Tg in which the red soil and the lateritic red soil were the main components of the organic carbon content and accounts for about 76.1%.② The organic carbon density was 12.13 kg/m^2 and it was below the national av- erage level. The zonal organic carbon density was in the following order： yellow soil〉red soil〉lateritic red soil〉latosol. ③ The distribution of the overall soil carbon density in the north area were higher than the south, and the surrounding regions were higher than the middle parts. The overall trend of the organic carbon density appears ＂U＂ shape along the longitude, the latitude and the altitude. The lower area of the organic carbon density was mainly affected by the Karst area.