黔中喀斯特地区3种林型土壤有机碳含量及垂直分布特征

在全球气候变化背景下,森林土壤有机碳库已成为全球碳循环研究的重点之一。研究以黔中喀斯特地区阔叶混交林、针阔混交林和灌木林为对象,分析其土壤及枯落物有机碳含量。结果表明:0-80cm土壤剖面的有机碳含量和碳密度均值表现为阔叶混交林(19.10g/kg,18.62kg/m2)>灌木林(9.21g/kg,9.67kg/m2)>针阔混交林(8.38g/kg,8.60kg/m2),且差异显著(P<0.05),说明同一地区不同林型土壤有机碳的积累和存储不同;3种林型0-20cm土层有机碳含量和碳密度均最大,且与各土层之间差异均显著(P<0.05),并随土层深度的增加而减少,说明森林土壤有机碳含量和密度分布有很强的表聚性,因此,应避免人为活动干扰,增加植被覆盖和减少水土流失;3种林型的土壤有机碳含量与土壤容重呈负相关关系,拟合度(R2)均较大,说明土壤有机碳含量与土壤容重拟合方程均较好;3种林型枯落物现存量和有机碳含量差异均显著(P<0.05),说明同一地区,不同林型的枯落物的积累和分解能力不同。

Organic Carbon Contents and Vertical Distribution Characteristics of the Soil in Three Forest Types of the Karst Regions in Central Guizhou Province

Under the global climate change context,the organic carbon bank of forest soil has become one of the main research topics concerning the global carbon cycle.Taking the mixed broadleaves,mixed conifers and broadleaves,and shrubs of the Karst regions in the middle of Guizhou as the research objects,this paper analyzed the organic carbon contents in the soil and litter.The research results showed that the average organic carbon contents and carbon density of the soil in the soil profile at 0-80 cm depth were separately 19.10 g/kg and 18.62 kg/m2 for mixed broadleaves,9.21 g/kg and 9.67 kg/m2 for shrubs,and 8.38 g/kg and 8.60 kg/m2 for mixed conifers and broadleaves,with significant differences(P<0.05) between the differents forest types,which indicated the accumulation and storage of organic carbon in the soil differed between the different forest types in the same region.The organic carbon contents and carbon density of the soil were the greatest in the 0-20 cm soil depths for all the three forest types,there was significant differences between the different soil layers(P<0.05) and the difference decreased with the increase of soil depths,which showed the organic carbon contents intensely tended to distribute in the surface of the forest soil.Therefore,intervention should be avoided and vegetation cover should be increased to lower soil and water loss.For all the three forest types,there was negative correlation between the organic carbon contents and the soil bulk weight and the fitting degree(R2) in the regression equations was considerably high showing comparatively good qualities of the fitting equations.The three forest types differed significantly from each other in both the present litter quantity and the organic carbon quantity(P<0.05),which proved the different forest types in the same region had different capacities in litter accumulation and decomposition.