文昌市不同森林类型土壤有机碳分布特征及其影响因素

Distribution Characteristics of Soil Organic Carbon in Different Forest Types and Its Influencing Factors in Wenchang City

土壤有机碳分布对于生态系统碳循环过程有重要意义,热带森林土壤存在高度空间异质性,不同森林类型下土壤有机碳的分布仍存在很大不确定性。本文以文昌市5种森林类型的表层土壤为研究对象,探究其有机碳分布特征,并通过相关性分析、逐步回归分析和冗余分析阐明影响土壤有机碳分布的主要影响因子。结果表明,文昌市5种森林类型土壤有机碳含量为6.18~35.71 g/kg,木麻黄人工林土壤有机碳含量最低,不利于土壤碳固存。有机碳分布表现为桉树人工林>人工混交林>次生林>相思人工林>木麻黄人工林。不同森林类型中有机碳含量变化与土壤中全氮含量、碳氮比变化一致。影响有机碳分布的主要因素为土壤全氮含量和碳氮磷化学计量比。本研究结果可以为热带地区土壤碳固存及森林生态系统管理保护提供参考。

The distribution of soil organic carbon is of great significance for the carbon cycling process in ecosystems.Tropical forest soils exhibit high spatial heterogeneity,and there is still significant uncertainty in the distribution of soil organic carbon under different forest types.This paper took the surface soil of five forest types in Wenchang City as the research objects,explored their organic carbon distribution characteristics,and clarified the main influencing factors on soil organic carbon distribution through correlation analysis,stepwise regression analysis,and redundancy analysis.The results showed that the soil organic carbon content of the five forest types were 6.18-35.71 g/kg in Wenchang City,and the soil organic carbon content of the forest plantations of Casuarina equisetifolia was the lowest,which was not conducive to soil carbon sequestration.The distribution of organic carbon was shown as follows:Eucalyptus robusta forest plantations>mixture plantations>secondary forests>Acacia auriculiformis forest plantations>Casuarina equisetifolia forest plantations.The changes in organic carbon content in different forest types were consistent with the changes in total nitrogen content and carbon nitrogen ratio in soil.The main factors affecting the distribution of organic carbon were soil total nitrogen content and carbon nitrogen phosphorus stoichiometric ratio.The results of this study could provide references for soil carbon sequestration and forest ecosystem management and protection in tropical regions.