中文摘要：

以科尔沁沙地典型樟子松林、油松林、杨树林和榆树林的土壤有机碳为对象，研究不同林分土壤有机碳含量的垂直分布特征及有机碳储量的大小，并分析根际与非根际土壤有机碳的关系。结果表明：科尔沁沙地各林分的土壤有机碳含量垂直分布格局不同，根际土有机碳含量均显著高于非根际土（P〈0．05），二者显著相关（P〈0．05），相关系数在0．54～0．82之间。土壤有机碳密度大小顺序为榆树林（6．35kg／m2）〉杨树林（5．34kg／m2）〉油松林（4．25kg／m2）〉樟子松林（4．11kg／m2），随着樟子松林龄增加，土壤有机碳密度呈现先降低后增加的趋势。各林分在0—20cm土层土壤有机碳储量占总储量的20．1％～33．8％，0—40cm土层所占比例为38．3％～68．2％。以上结果说明，科尔沁沙地典型林分土壤有机碳垂直分布较深，且主要来源于根系；该区土壤有机碳储量低于全国平均水平，但人工林种植增加了土壤有机碳储量。

英文摘要：

Based on the investigation of the soil organic carbon content at different soil layers, the relationship between soil organic carbon content and rhizospher effect, and the vertical distribution characteristics of soil organic carbon content and soil organic carbon storage of Pinus sylvestris var. monogolica forest, Pinus tabulaeformis forest, Populus sirnonii forest and Ulmus pumila forest in Horqin sandy land were analyzed. The results showed that there were different distribution characteristics of soil organic carbon content in dif- ferent stands. The soil organic carbon contents in the rhizosphere soil were significantly higher than that in the non-rhizosphere soil in all stands （P〈0.05）. Furthermore, there was significant correlation between soil organic carbon content in the rhizosphere soil and that in the non-rhizosphere soil （P〈0.05）, and the corre- lation coefficient between them was 0.54~0.82. The quantity order of soil organic carbon density was U. pumila forest （6.35 kg/m2） 〉P. simonii forest （5.34 kg/m2） 〉P. tabulaeformis forest （4.25 kg/m2） P. sylvestris var. monogolica forest （4.11 kg/m2）. With increasing forest age of P. sylvestris var. monogo- lica, the soil organic carbon density firstly reduced, and then rose gradually. Soil organic carbon storage at 0 --20 cm soil layer accounted for 20.1~33.8% of the total storage, and that at 0--40 cm soil layer accoun- ted for 38.3~68.2% of the total storage. These results indicated that the distribution depth of soil organic carbon was deeper in Horqin sandy land forests. The percent of soil organic carbon from 54% to 82% was transformed by rhizosphere. The soil organic carbon storage in Horqin sandy land was less than the average value of China. However, these plantations increased soil organic carbon storage in sandy land.