自然生长和人为影响下土壤碳氮含量差异及影响因素

Difference and Influencing Factors of Soil Carbon and Nitrogen Contents Under Natural Growth and Human Influence

[目的]深入探讨环青海湖区近30年未变动放牧草地和耕地土壤碳氮含量影响因素,以期为该区土地利用优化管理提供参考。[方法]基于有幸在该区找到未变动放牧草地和耕地,采用前期研究工作中的多个指标,利用一元和多元回归模型进一步分析土壤碳氮含量主导因素。[结果]该区草地和耕地土壤理化指标基本以30 cm土层深度为界发生明显变化;从回归模型中可以看出,由于受到人类活动影响,耕地土壤碳氮含量受土壤理化指标影响较小,而草地土壤作为未扰动土壤,在自然发育背景下土壤碳氮主导因素明显多于耕地。[结论]土地利用变化显著影响了土壤性状,在该区减少土地扰动能有效减缓土地荒漠化进程。

[Objective]The factors influencing the soil carbon and nitrogen content of unchanged grazed grassland and cultivated land in the Qinghai Lake area for the past 30 years were thoroughly investigated,with a view to providing reference for optimal land use management in the area.[Methods]Further analysis of the dominant factors of soil carbon and nitrogen contents was carried out by using univariate and multiple regression models.[Results]The soil physicochemical indexes of grassland and cultivated land changed obviously with 30 cm soil depth as the boundary.It can be seen from the regression model that soil carbon and nitrogen contents in cultivated land are less affected by soil physical and chemical indexes due to the influence of human activities,while grassland soil,as an undisturbed soil,has significantly more dominant factors on soil carbon and nitrogen than those of the cultivated land under the natural development background.[Conclusion]Land use change significantly affects soil properties,and reducing land disturbance in the area can effectively slow down the process of land desertification.