重庆四面山五种人工林土壤有机碳储量研究

The Soil organic carbon storage study under five plantations in the simian mountain of Chongqing

对重庆四面山杉木纯林、杉木×马尾松、杉木×马尾松×木荷、木荷×石栎×枫香×香樟、木荷×石栎人工林进行了有机碳储量研究。运用网格取样法取样,每个样地各层各取样81个,共计取样810个。结果表明:(1)林分类型不同,A层土壤有机碳含量总体差异显著(p<0.05)。在此五种林分类型中,土壤平均有机碳含量以杉木人工纯林为最高,石栎木荷枫香香樟人工混交林为最小;B层土壤有机碳含量总体差异不显著(p>0.05)。在垂直剖面上,五种人工林均差异显著(p<0.05),且表现出随着土层深度的增加,林下土壤有机碳含量随之减小,体现出土壤有机碳含量的表聚作用。(2)有机碳储量规律基本与土壤有机碳含量规律一致。在垂直剖面上,此五种人工林有机碳储量均差异显著(p<0.05),表现出随着土层深度的增加而减小的规律。不同林种类型、同一土层深度或是不同土层深度、同一林种类型其有机碳储量变异系数大小均不一样,这说明此五种林地土壤普遍存在空间异质性且其异质程度不一样。(3)就A土层而言,本研究区五种人工林平均有机碳密度为5.34 kg:m-2,比相关研究的重庆市土壤有机碳密度3.11 kg:m-2,全国森林土壤有机碳密度4.24 kg:m-2,全国土壤有机碳密度2.67 kg:m-2等分别多出71.70%,25.94%,100%。

In this paper ,we had researched the soil organic carbon storage under five plantations, namely pure fir forest（cunninghamia lanceolata）, fir and pine（pinus massoniana） mixed forest, and three other mixed broad-leaved forest（Cunninghamia lanceolata×Pinus massoniana×Schima superb, Schima superba×Cinnamomum camphora×Lithocapus glaber×Liquidambar formsana and Schima superba×Lithocarpus glaber）, in the simian mountain of Chongqing. A grid sampling method was used to take 81 samples in every layer of every sample plot, totally 810 samples. The results indicated that （1） there is a significant difference （p 〈 0.05） in the average SOC content of A layer under different forest types. The pure fire forest（cunninghamia lanceolata） had the highest SOC content and the Schima superba×Cinnamomum camphora×Lithocapus glaber×Liquidambar formsana had the lowest. The difference in the average SOC content of B layer in different forest types was not significant （p〉0.05）. In the vertical section, five kinds of plantations all showed a significant difference （p〈0.05）, and the SOC content decreased with depth, reflecting the assembled action in the surface layer. （2） The rule of soil organic carbon storage was almost consistent with that of soil organic carbon content. In the vertical section,the organic carbon storage under five plantations were significant different （p〈0.05） and decreased with the soil depth. The variable coefficient of the organic carbon storage were quite different between the soil depths or between the forest types, indicating that the spatial heterogeneity was ubiquitous and the degree of heterogeneity were different. （3） In terms of the A soil layer, the average organic carbon density of the five plantations was 5.34 kg·m^-2, which was 71.70%higher than the previou results （3.11 kg·m^-2） in Chongqing, 25.94%higher than the national forest soil organic carbon density （4.24 kg·m^-2）, 100%higher than the national soil organic carbon density （2.67 kg·m^-2）.