海南岛东南部热带雨林土壤易氧化有机碳特征及影响因素

Characteristics and Influencing Factors of Easily Oxidized Organic Carbon in Tropical Rain Forest Soil in Southeast Hainan Island

以海南岛东南部热带雨林土壤为研究对象,探讨土壤易氧化有机碳的含量、分布规律及其影响因素,旨在为深入了解热带雨林山地土壤易氧化有机碳的累积以及淋溶的影响,以期为热带雨林土壤碳循环及固碳能力研究方面提供理论依据。结果显示:(1)海南岛东南部热带山地雨林0~50 cm土壤剖面易氧化有机碳含量变化范围为2.29~5.47 g/kg,均值为4.15 g/kg。(2)在同一海拔梯度内,研究区土壤易氧化有机碳含量随着土层深度的加深而逐渐降低,研究区土壤易氧化有机碳在各海拔梯度内变异系数差别不大;同一深度土层中,随海拔梯度的升高易氧化有机碳含量均呈现逐渐增加趋势。(3)研究区不同土壤易氧化有机碳含量与海拔呈现极显著或显著正相关,表层(0~10 cm)土壤易氧化有机碳含量与土壤pH呈显极著负相关,与坡度呈显著负相关;土壤易氧化有机碳与机械组成(黏粒、粉粒、砂粒)均未达到显著水平。(4)不同土层土壤易氧化有机碳含量分布与海拔、坡度和土壤pH的一元线性回归分析结果与相关性分析结果一致。研究结果表明,海拔、坡度和土壤pH是影响研究区土壤易氧化有机碳含量的主要因子。

Taking the soil of the tropical rain forest in the southeast of Hainan Island as the research object,the content,distribution and influencing factors of soil easily oxidized organic carbon were discussed through sample collection and laboratory sample determination in the study area by using the single factor analysis of variance and the least significant difference method(LSD).The purpose of this study was to further understand the accumulation and leaching effects of easily oxidized organic carbon in the soil of the tropical rain forest mountain.The results showed that:(1)In the 0-50 cm soil profile of the tropical mountain rainforest in the southeast of Hainan Island,the soil easily oxidized organic carbon content ranged from 2.29-5.47 g/kg,with an average of 4.15 g/kg.(2)Within the same elevation gradient,the content of soil easily oxidized organic carbon in the study area decreased gradually with the deepening of soil depth,and the variation coefficient of soil easily oxidized organic carbon in the study area had little difference in each elevation gradient.In the same depth soil layer,the content of easily oxidized organic carbon showed a gradual increasing trend with the increase of elevation gradient.(3)The content of easily oxidized organic carbon in different soils in the study area showed an extremely significant or significant positive or positive correlation with the altitude,and the content of easily oxidized organic carbon in the surface layer(0-10 cm)soil showed an extremely negative correlation with soil pH,and a significant negative correlation with slope.In this study,soil easily oxidized organic carbon and mechanical composition(clay,silt,sand)did not reach a significant level.(4)Through the unitary linear regression analysis of the distribution of soil easily oxidized organic carbon content in different soil layers and the elevation,slope and soil pH,the results showed that it was consistent with the correlation analysis results.The results showed that elevation,slope and soil pH were the main factors affecting the content of soil easily oxidized organic carbon.