祁连山中段典型植被土壤有机碳密度研究

Study on soil organic carbon density of typical vegetation in middle Qilian mountains

【目的】探讨祁连山不同植被类型土壤有机碳含量及密度的分布规律,为祁连山区土壤碳库的科学管理及精确估算提供科学依据。【方法】选择分布在祁连山排露沟流域的青海云杉林、灌木林、草地等3种典型植被为研究对象,通过野外调查取样和室内测定分析,研究了3种植被类型土壤有机碳含量及密度的分布特征。【结果】3种植被类型0~60 cm土层平均有机碳含量为31.74~65.19 g·kg-1,青海云杉林土壤有机碳含量显著高于灌木林和草地(P <0.05),但灌木林与草地之间差异不显著(P> 0.05);0~60 cm土层平均有机碳密度为12.61~18.65 kg·m-2,青海云杉林与灌木林之间差异不显著(P> 0.05),但与草地差异显著(P <0.05);灌木林土壤有机碳含量及密度变异程度较为剧烈。随着土层深度的增加,青海云杉林土壤有机碳含量呈先增大后减小趋势,10~20 cm土层有机碳含量显著高于其它土层,而其它土层含量较为接近;灌木林和草地土壤有机碳含量呈减小趋势,具有明显的"表聚现象"。随着土层深度的增加,青海云杉林土壤有机碳密度也呈先增大后减小趋势,10~20 cm土层有机碳密度显著高于其它土层,表层有机碳密度明显低于其它土层;灌木林和草地土壤有机碳密度呈减小趋势。0~40 cm土层有机碳密度占整个剖面的66.99%~77.56%,40 cm以下土壤有机碳密度较小。【结论】祁连山区青海云杉林更有利于土壤有机碳的储存和积累,3种植被类型大部分土壤有机碳存储在0~40 cm土层。

【Objective】In order to provide scientific basis for scientific management and accurate estimation of soil carbon pool in Qilian mountains, the distribution law of soil organic carbon content and density in different vegetation types of Qilian mountains was explored.【Method】We selected Picea crassifolia forest, shrubs and grassland which lived in Pailugou catchment of Qilian mountains as objects. By field investigation and laboratory analysis, the distribution characteristics of soil organic carbon content and density of different vegetation types were studied.【Result】the soil organic carbon content of 0-60 cm soil layer of three vegetation types was 31.74-65.19 g·kg-1, the soil organic carbon content of Picea crassifolia forest were higher than that of shrubs and grassland, and there was significant difference between Picea crassifolia forest and shrubs, grassland(P < 0.05), but no significant difference between shrubs and grassland(P > 0.05).the average soil organic carbon densitywas 12.61-18.65 kg·m-2. The soil organic carbon density of Picea crassifolia forest washigher than that of shrubs and grassland, but there was no significant difference between Picea crassifolia forest and shrubs(P > 0.05), and significant difference between Picea crassifolia forest and grassland(P < 0.05).the variation degree of soil organic carbon content and density in shrubs was more intense. With the increase of soil depth, soil organic carbon content of Picea crassifolia forest increased at first and then decreased. the soil organic carbon content in 10-20 cm soil layer was significantly higher than that in other soil layers, while the content in other soil layers was relatively close;The soil organic carbon content of shrubs and grassland decreased gradually with the deepening of soil layer, and had obvious surface accumulation phenomenon.With the increase of soil depth, soil organic carbon density of Picea crassifolia forest increased at first and then decreased. The soil organic carbon density in 10-20 cm soil layer was significantly higher than that in other soil layers, and the organic carbon density in surface layer was significantly lower than that in other soil layers;the soil organic carbon density of shrubs and grassland decreased gradually with the deepening of soil layer. The organic carbon density of 0-40 cm soil layer accounted for 66.99%-77.56% of the whole profile, and the soil organic carbon density below 40 cm was small.【Conclusion】Picea crassifolia forest was more beneficial to the storage and accumulation of soil organic carbon.Most of the soil organic carbon was stored in 0-40 cm soil layer in the three vegetation types.