Soil Carbon Changes and Its Influencing Factors in Major Forest Types in the Subtropical Area of Yunnan Province
[Objective]As the largest carbon pool in terrestrial ecosystems,changes in forest soil organic carbon(SOC)have a significant impact on the global carbon cycle.By exploring the differences in SOC in different forest types and its influencing factors,we aim to provide a theoretical basis for forest carbon sink management.[Method]Eucalyptus plantation forest(EP),Pinus pure forest(PK)and evergreen broadleaf forest(EB)in Lancang County were used in this study.ANOVA and redundancy analysis were used to analyze SOC,soil organic carbon density(SOCD)and carbon to nitrogen ratio(C/N)levels and vertical distribution patterns of the three forest land types at different depths of 0～20 cm,20～40 cm and 40～60cm and reveal their main influencing factors.[Result](1)There were significant differences in SOC among the three forest types in the 0-60 cm soil layer.Its variation range was 14.89～22.05 g·kg-1,which was higher than the national forest soil organic carbon level,with EB forest having the highest(22.05 g·kg-1);The SOCD ranged from 3.42 to 4.12 kg·m-2,with the highest in EB forests(4.12 kg·m-2);The soil C/N ranged from 12.99 to 13.82,with EP forests being the highest(13.82);(2)As the soil layer deepens,the SOC,SOCD,and C/N of the three types of forest land showed a downward trend,with the EB soil or-ganic carbon content and density showing the most obvious downward trend;(3)The organic carbon con-tent and density of the three types of forest land were mainly affected by soil density,organic matter,total nitrogen,hydrolytic nitrogen,and total phosphorus,with little impact from environmental and topographical factors;The main influencing factors of soil C/N were organic matter,pH,and aspect,while environmental factors had a relatively small impact on it.[Conclusion]The soil of EP and EB have advantages in carbon sink,while the carbon sink function of PK is weaker.Soil carbon content is more influenced by soil physico-chemical indexes and less influenced by environmental and topographic factors.
万方数据
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