为了评价土壤性质对土壤有机碳含量的影响,运用通径分析方法研究了江西大岗山杉木人工林下土壤有机碳含量与土壤性质的关系。结果表明:在杉木人工林的整个发育过程中,土壤有机碳含量和土壤各性质表现出明显的规律性变化;土壤性质通过直接作用和间接作用共同影响着土壤有机碳的含量和分解转化方向,但不同土壤性质的影响机理不同。在土壤系统中,碱解氮量、细菌数量和真菌数量以及它们的共同作用决定了土壤有机碳含量的大部分变异,是影响土壤有机碳含量变化的主导因素,有效磷含量和放线菌数量由于直接正效应和间接负效应相抵,因而对土壤有机碳含量的决定程度较小,总孔隙度和速效钾含量对有机碳含量虽也表现出一定的直接效应影响,但影响程度较低;和简单相关或多元回归分析方法相比,通径分析能更加客观和全面地评价土壤性质对土壤有机碳含量的影响作用。
In order to assess extents of the influences of soil properties on soil organic carbon(SOC),the relations between SOC content and soil properties under Chinese fir plantations were studied through path analysis in Dagang mountain of Jiangxi Province.The results showed that the entire developing process of Chinese fir plantations,the significant regular variation of SOC content and soil properties were found.SOC content and the direction of decomposition and transformation were affected by direct and indirect effects of soil properties,but their influence mechanism were different.Alkali-hydrolyzable nitrogen content,the numbers of bacteria and fungi were determined largely by the variation of SOC content,and there are leading factors influencing SOC content variation.The positive direct effects of available phosphorus content and the number of actinomycetes were counteracted by the negative indirect effects on them,so showed less decisive degree of SOC content.Total porosity and readily available potassium also showed certain direct effects on SOC content,but influence degree was comparatively smaller.Compared with correlation analysis and stepwise regression analysis,path analysis could objectively and comprehensively assess the influences of soil properties on SOC content.