不同发育阶段杉木林土壤有机碳变化特征及影响因素

对江西大岗山地区不同发育阶段杉木林林地土壤有机碳变化特征进行了研究,并利用相关分析和逐步回归分析方法探讨了土壤因子对其的影响.结果表明,不同发育阶段土壤有机碳含量随土壤深度的增加而降低,各层次有机碳含量表现出明显的变异特征,变异程度为:40～60 cm土层>20～40 cm土层>0～20 cm土层,其中中龄林土壤变异最为显著;随杉木的生长发育,土壤有机碳含量从幼龄林到中龄林呈下降趋势,中龄林到过熟林则呈上升趋势;土壤有机碳含量与全N量、碱解N量、有效P含量等土壤因子密切相关;建立的从幼龄林到过熟林各阶段的土壤有机碳回归方程具有较高的回归精度,比较标准化回归系数法处理显示,土壤N状况是影响土壤有机碳变异的主导因子.

The Var ia tion Character istics of So ilOrgan ic Carbon and Its InfluenceFactor in D ifferent Developing Stages of Chinese f ir Planta tion s

The variation characteristics of soil organic carbon ( SOC) in different develop ing stages of Chinese firp lantations were studied in Dagang mountain of J iangxi Province. Correlation analysis and stepwise regressionanalysiswere used to investigate the influence of soil factors on SOC content. Results showed that SOC contentdecreased with increasing soil dep th. Significant variation characteristics of SOC contentwere found in different soillayers, with coefficient variation in the order of 40 - 60 cm > 20 - 40 cm > 0 - 20 cm, especially in the mediumforest soil. With the growth and development of Chinese fir p lantations, SOC content decreased from juvenile tomedium, and then increased from medium to over-mature. The SOC content had close correlations with totalnitrogen content and alkali-hydrolyzable nitrogen content. The SOC regression equations in different develop ingstages of Chinese fir p lantationswere established with high regression estimation p recision. Compared Beta suggestedthat soil nitrogen was the leading factor of SOC content variation.