桂东南不同林分类型土壤有机碳储量及分配特征

Organic carbon storage and distribution characteristics of different stand types soil in southeastern Guangxi

  • 摘要: 【目的】探索桂东南典型林分类型土壤有机碳储量的组成特点和分布规律,为了解林业碳汇在应对气候变化的作用,以及促进陆地生态系统碳循环和林业碳汇发展提供理论依据。【方法】以博白林场的杉木(Cunnighamia lanceolata)、红锥(Castanopsishystrix)及巨尾桉(Eucalyptusgrandis×urophylla)3种人工林作为研究对象,运用野外采样和室内化验检测分析的方法,测算不同林分类型土壤的容重、有机碳密度、有机碳含量、有机碳储量及不同土层土壤有机碳贡献率,探讨桂东南主要林分类型土壤有机碳储量及其垂直分布特征。【结果】桂东南3种典型林分类型土壤有机碳密度差异明显,红锥林的土壤有机碳密度平均值最高,为4.50 kg/m2,巨尾桉林的土壤有机碳密度平均值最低,显著低于其他类型(P<0.05,下同);各林分土壤有机碳密度随土壤深度逐渐降低。巨尾桉林土壤有机碳含量显著低于红锥林和杉木林,3种林分土壤有机碳含量均随土层深度加深而逐渐降低。不同林分土壤总有机碳储量排序依次为红锥林>杉木林>巨尾桉林,红锥和杉木林土壤的总有机碳储量分别为135.13和133.41 t/ha,均显著大于巨尾桉林。3种林分不同土层土壤对有机碳储量贡献率均随土层加深而逐渐降低。【结论】红锥和杉木林分土壤有机碳含量和储量较巨尾桉林更高。在人工林改造过程中,选择种植长周期的红锥和杉木,更有利于土壤有机碳储量的积累与固定,具有更好的土壤碳汇效益。

     

    Abstract: 【Objective】To explore the composition characteristics and distribution rules of soil organic carbon stocks of typical stand types in southeastern Guangxi, and provide theoretical basis for understanding the role of forestry carbon sequestration in coping with climate change, and promoting carbon cycle in terrestrial ecosystem and the development of forestry carbon sequestration. 【Method】Cunnighamia lanceolata, Castanopsis hystrix and Eucalyptus grandis×urophylla plantations were studied in Bobai Forest Farm. The bulk density, organic carbon density, organic carbon content and organic carbon storage of soil of different stand types and the contribution rate of soil organic carbon in different soil layers were measured by field sampling and laboratory analysis, and the characteristics of soil organic carbon storage and vertical distribution of main stand types in southeastern Guangxi were discussed. 【Result】There were obvious differences in soil organic carbon density among the three typical stands in southeastern Guangxi. The average soil organic carbon density of C. hystrix plantation was the highest(4.50 kg/m2), and that of E. grandis×urophylla plantation was the lowest,which was significantly lower than other types(P<0.05, the same below); soil organic carbon density in each stand decreased gradually with soil depth. The soil organic carbon content of E. grandis×urophylla plantation was significantly lower than C. hystrix and C. lanceolata, and the soil organic carbon content of the three stands gradually decreased with the depth of the soil layer. The soil organic carbon density of the three stand types was ranked as C. hystrix plantation>C.lanceolata plantation>E. grandis×urophylla plantation.The soil organic carbon storages of C. hystrix plantation and C. lanceolata plantation were 135.13 and 133.41 t/ha, which significantly greater than that of E. grandis×urophylla plantation.The contribution rate of soil organic carbon storage in different soil layers of the three stand types gradually decreased with the depth of the soil layer. 【Conclusion】Among the three stands, the soil organic carbon content and storage of C.hystrix plantation and C. lanceolata plantation are higher than that of E. grandis×urophylla plantation. In the process of plantation transformation, selecting long-term C. hystrix and C. lanceolata is more conducive to the accumulation and fixation of soil organic carbon storage, which has better soil carbon sink benefits.

     

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