基于结构方程模型的东北地区主要旱田土壤有机碳平衡关系研究

Equilibrium relationships of soil organic carbon in the main croplands of northeast china based on structural equation modeling

土壤有机碳平衡是一个复杂的过程,是潜变量与潜变量,潜变量与可测变量及可测变量之间相互作用的结果。结构方程模型的建立很好地描述了这一复杂关系。应用2011年东北地区敦化、榆树、公主岭、昌图和阜新5个典型县(市)农田表层土壤有机碳(0—20 cm)数据,建立了东北地区主要旱田土壤有机碳平衡关系结构方程模型,探讨了影响有机碳平衡关系的各潜变量和可测变量的相互影响关系。结果表明:在土壤有机碳的平衡过程中,潜变量之间(气候环境、土壤性质和人为管理)具有两两相关性,土壤性质对有机碳平衡具有直接正向作用,其路径系数为1.01;气候环境和人为管理通过土壤性质传递并影响土壤有机碳平衡,且气候环境的影响力大于人为管理的影响力,其路径系数分别为1和0.87。因此,针对有机碳平衡关系计算出的路径系数,需要强化人为管理在土壤有机碳平衡过程中的作用,特别要在耕作方式上加强管理,促使有机碳平衡向更优化方向发展。

Soil organic carbon equilibrium （SOCE） is a complex process determined by the interactions between of different latent variables, or between measurable variables, and between the latent and measurable variables. The interaction relationships could be well expressed by the structural equation modeling （SEM）. Based on the surface soil （0--20 cm） data of some typical counties （ Dunhua, Yushu, Gongzhuling, Changtu and Fuxin） in the Northeast China, a SEM of soil organic carbon equilibrium in those counties was simulated, and the relationships of SOCE as affected by different variables were evaluated. The results indicated that there were significant interactions between latent variables （climate regimes, soil properties and management practices）. Soil properties had a direct positive effect on SOCE with a path coefficient 1.01, while climate regimes and management practices influenced on SOCE indirectly through soil properties. Moreover, the influence of climate was greater than that of the management with path coefficients of 1 and 0.87, respectively. According to the path coefficients activities （ especially development. calculated by the SEM on tillage practices） , on SOCE, it is very important to pay more attention to the effect of human process of SOCE and it is extremely crucial to optimize SOCE by a better