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以我国亚热带四类典型景观单元表层土壤为对象,对比分析了土壤有机碳(SOC)含量和密度特征.结果表明,四类景观单元SOC含量加权平均值差异明显,以平原湖区加权平均值最高(25.10g·kg-1),其次为喀斯特低山(20.84g·kg-1)和红壤低山(17.75g·kg-1),红壤丘陵平均值最低(12.07g·kg-1).四类景观单元SOC含量变异系数在24.06%～43.76%之间,均属于中等程度变异.平原湖区景观SOC含量主要分布区高于20g·kg-1,其它三类景观单元主要分布区则相反.四类景观单元SOC密度加权平均值大小顺序与SOC含量高低极为一致,其顺序为平原湖区(6.12kg·m-2)>喀斯特低山(4.30kg·m-2)>红壤低山(4.25kg·m-2)>红壤丘陵(3.04kg·m-2).研究结果揭示成土母质、耕作强度、地形差异和土地利用方式比例是SOC含量景观变异的主要原因,亚热带地区典型景观单元土壤可能是我国重要的碳库.
The soil organic carbon (SOC) content and density characteristics of four typical subtropical landscape units in China were comparatively analyzed.The results showed that there were significant differences in the weighted mean values of SOC content between the four types of landscape units, with the highest weighted average Followed by Karst low mountain (20.84g · kg-1) and red soil low mountain (17.75g · kg-1), and red soil hilly average was the lowest (12.07g · kg-1) The coefficient of variation of SOC content of landscape units ranged from 24.06% to 43.76%, which belonged to medium degree of variation.The main distribution area of SOC content in plain lake area was higher than 20g · kg-1, while the other three types of landscape units were mainly distributed in four areas The order of the weighted average of SOC density of landscape units is consistent with that of SOC, and the sequence is as follows: plain Lake area (6.12kg · m-2)> Karst low mountain (4.30kg · m-2)> red soil lower hill (4.25kg · m -2)> red soil hills (3.04 kg · m-2). The results revealed that the ratio of soil parent material, tillage intensity, topography and land use pattern was the main reason for the SOC content variation. The typical landscape unit soil in subtropical area may be China Important carbon stock.