长白山北坡云冷杉阔叶混交林土壤有机碳分布特征及其影响因素

Distribution Characteristics and Influencing Factors of Soil Organic Carbon in Spruce-fir broad-leaved Mixed Forest on North Slope of Changbai Mountains

森林土壤碳库在陆地生态系统中发挥着重要作用,对于维持全球碳平衡、调节全球碳循环和降低大气CO_(2)浓度等具有重要意义。森林土壤有机碳(SOC)是森林土壤碳库中最重要的组成部分,是调节森林土壤肥力和生产力、养分有效性的关键因素,为林木和土壤微生物生长提供能量和营养物质。以吉林汪清林业局云冷杉阔叶混交林为研究对象,选择采伐强度分别为6.29%和11.22%,面积为1 hm^(2)的两块样地,探究不同采伐强度和土壤深度下土壤有机碳含量和储量的分布特征,并分析土壤有机碳与土壤理化性质之间的相关性和灰色关联度,以期揭示长白山北坡森林土壤有机碳分布规律。结果表明:土壤有机碳在0—20 cm土层均出现积聚现象;随土层深度增加,土壤有机碳含量和储量逐渐降低,且其空间变异程度均为中等。在0—20 cm和20—40 cm土层中,土壤有机碳含量和碳储量均表现为样地Ⅱ(采伐强度为11.22%)>样地Ⅰ(采伐强度为6.29%)。两块样地土壤C/N均高于全球土壤C/N均值,且随土壤深度增加呈现上升趋势。土壤有机碳与全氮、全磷、有效磷呈显著或极显著正相关关系,与土壤密度呈极显著负相关(P<0.01)。不同土壤理化性质与土壤有机碳含量的关联程度均较高。该研究表明云冷杉阔叶混交林土壤有机碳具有表聚性,且受土壤全氮、全磷、有效磷含量和土壤密度等影响较大,不同样地及不同土壤深度之间有机碳含量和储量差异极显著。

Forest soil carbon pools play an important role in terrestrial ecosystems and are of great significance for maintaining global carbon balance,regulating global carbon cycle,and reducing atmospheric CO_(2) concentration.As the most important component of forest soil carbon pools,forest soil organic carbon(SOC)is the key factor in regulating forest soil fertility,productivity,and nutrient availability by providing energy and nutrients for tree growth and soil microorganisms.The spruce-fir broad-leaved mixed forests in Wangqing Forestry Bureau of Jilin Province were taken as the research object,two 1-ha plots with cutting intensities of 6.29%and 11.22%were selected to explore the distribution characteristics of the SOC content and stock under different cutting intensities at varied soil depths,and to analyze the correlation and gray correlation degree between SOC and soil physico-chemical properties.The results showed that SOC accumulated in the 0–20 cm soil.With the increase of soil depth,the SOC content and stock along soil profile decreased gradually with a moderate spatial variability.The soil C/N ratio of the two plots was higher than the global average,and showed an upward trend with an increase of soil depth.The SOC had a significant or highly significant positive correlation with soil total nitrogen,total phosphorus,and available phosphorus,a highly significant negative correlation with soil bulk density(P<0.01),and no significant correlation with soil pH and readily available potassium(P>0.05).The relationship between soil physico-chemical properties and SOC content was high.The SOC in spruce-fir broad-leaved mixed forests showed surface accumulation,and was greatly affected by soil total nitrogen,total phosphorus,available phosphorus content,and soil bulk density.There were highly significant differences in organic carbon content and stock between plots and among various soil depths.