【摘要】 明晰不同林分密度下土壤有机碳组分含量及碳库特征，以期为确定刺槐林适宜人工造林密度和评价水土保持效益提供科技支撑。设置不同密度(700、1 500、1 800、2 400、3 000、3 500 plant·hm^-2)刺槐样地，以荒草地为对照，分析0-40 cm土层土壤有机碳组分及变化规律，计算碳库活度指数（CPAI）、碳库指数（CPI）以及碳库管理指数（CPMI），解析不同密度刺槐林地土壤碳库变化，并探讨土壤理化性质对土壤有机碳及其组分变化的影响。结果表明：不同密度刺槐林地土壤有机碳及其组分的含量均随着土层深度的增加而减少，平均土壤有机碳（SOC）含量为：6.80 g·kg^-1(1 800 plant·hm^-2)>5.01 g·kg^-1(1 500 plant·hm^-2)>4.73 g·kg^-1 (2 400 plant·hm^-2)>4.17 g·kg^-1 (3 000 plant·hm^-2)>2.78 g·kg^-1 (700 plant·hm^-2)>2.68 g·kg^-1 (3 500plant·hm^-2)>0.52 g·kg^-1 （CK）。随着刺槐人工林密度的增大，土壤有机碳组分及CPMI呈先增大后减小的趋势，中密度刺槐林分土壤有机碳组分含量及CPMI最大。与对照相比，0-40 cm土层，6种林分密度的土壤易氧化有机碳、稳定态有机碳含量、可溶性有机碳、颗粒有机碳和矿质结合态有机碳分别提高了77.3%-94.9%、55.8%-91.3%、86.0%-94.2%、81.4%-93.5%和79.8%-91.2%。6种林分密度土壤碳库管理指数均高于100%。相关关系分析表明土壤总有机碳含量与各有机碳组分均呈极显著正相关（P<0.010）；冗余分析表明土壤全氮对土壤有机碳及其组分变化的解释率最大。因此，从森林土壤固碳功能而言，晋西黄土区刺槐人工林的适宜林分密度为1 800 plant·hm^-2，该林分密度能较好提高土壤碳养分供给水平与碳库稳定性。更多还原

【Abstract】 To clarify the soil organic carbon content and characteristics of the carbon pool under different stand densities,to provide scientific and technological support for determining the suitable planting density of Robinia pseudoacacia forests,and to evaluate the benefits of soil and water conservation,different densities (700,1 500,1 800,2 400,3 000,3 500 plants·hm^-2) of the locust plot,soil organic carbon composition,and its variation in the 0-40 cm soil layer were analyzed,and the carbon pool activity index （CPAI）,carbon pool index （CPI）,and Carbon Pool Management Index （CPMI） were calculated.Changes in the soil carbon pool under different densities of Robinia pseudoacacia forest were analyzed,and the effects of soil physical and chemical properties on the changes in soil organic carbon and its components were discussed.The results showed that the content of soil organic carbon and its components decreased with increasing soil depth.The average content of soil organic carbon （SOC） was 6.80 g·kg^-1 (1 800 plant·hm^-2)>5.01 g·kg^-1(1 500 plant·hm^-2)>4.73 g·kg^-1 (2 400 plant·hm^-2)>4.17 g·kg^-1 (3 000 plant·hm^-2)>2.78 g·kg^-1 (700 plant·hm^-2)>2.68 g·kg^-1 (3 500plant·hm^-2)>0.52 g·kg^-1 （CK）.With an increase in the density of Robinia pseudoacacia plantations,the content of soil organic carbon and CPMI contents first increased and then decreased.Compared with the control,0-40 cm soil layer,the contents of soil easily oxidized organic carbon,stable organic carbon,soluble organic carbon,particulate organic carbon,and mineral-bound organic carbon increased by 77.3%-94.9%,55.8%-91.3%,86.0%-94.2%,81.4%-93.5%and 79.8%-91.2%,respectively.The soil carbon pool management indices of the six stand densities were higher than 100%.Correlation analysis showed that the total soil organic carbon（TOC） was positively correlated with all organic carbon components （P<0.01）,and redundancy analysis showed that total soil nitrogen（TN） had the highest explanation rate for the changes in soil organic carbon and its components.Therefore,the suitable stand density of Robinia pseudoacacia plantations is 1800 plants·hm^-2 in the loess area of western Shanxi province,which can improve the supply level of soil carbon and the stability of the carbon pool.更多还原