基于CENTURY模型的甘南高寒草甸土壤氮动态模拟研究

Dynamic simulation of soil nitrogen in Gannan alpine meadow based on CENTURY model

【目的】为明确甘南高寒草甸土壤氮素的时空变化特征及影响因素。【方法】基于CENTURY模型模拟1971-2020年甘南高寒草甸土壤有机氮及矿质氮含量,并以此为依据实现研究区土壤氮素时空分布的可视化。运用经典统计学及地统计学分析方法,揭示甘南高寒草甸土壤氮素时空变异特征。在此基础上,运用相关分析及结构方程模型探讨各环境因子对甘南高寒草甸土壤氮素的影响,从而确定甘南高寒草甸土壤氮素的主要影响因子。【结果】1971-2020年研究区土壤有机氮均具有中等空间变异性。土壤有机氮最高值为2000年的714.054 g/m^(2),土壤矿质氮最高值出现在1993年的13.257 g/m^(2)。在空间分布上,甘南高寒草甸土壤总有机氮及总矿质氮呈现出由西向东逐渐递减趋势,且土壤总矿质氮含量随着土壤深度增加而显著减少。【结论】土壤氮素与环境因子相关分析及结构方程模型结果表明,降水量、海拔、土壤有机质含量及粉粒含量对土壤有机氮及矿质氮含量为正效应。砂粒含量及温度对土壤有机氮及矿质氮含量的作用为负效应。

【Objective】In order to clarify the temporal and spatial variation characteristics and influencing factors of soil nitrogen in Gannan alpine meadow.【Method】This study simulated the contents of organic nitrogen and mineral nitrogen in Gannan alpine meadow soil from 1971 to 2020 based on the CENTURY model,and realized the visualization of the temporal and spatial distribution of soil nitrogen in the study area.By using classical statistics and geo-statistical analysis methods,the temporal and spatial variation characteristics of soil nitrogen in Gannan alpine meadow were revealed.On this basis,the correlation analysis and structural equation model were used to explore the influence of various environmental factors on soil nitrogen in Gannan alpine meadow,so as to determine the main influencing factors of soil nitrogen in Gannan alpine meadow.【Result】The results showed that the soil organic nitrogen in the study area had medium spatial variability from 1971 to 2020.The highest value of soil organic nitrogen was 714.054 g/m^(2) in 2000,and the highest value of soil mineral nitrogen was 13.257 g/m^(2) in 1993.In spatial distribution,the total organic nitrogen and total mineral nitrogen in the alpine meadow of Gannan showed a decreasing trend from west to east,and the total mineral nitrogen content in the soil decreased significantly with the increase of soil depth.【Conclusion】Correlation analysis between soil nitrogen and environmental factors and structural equation model showed that precipitation,altitude,soil organic matter content and silt content had positive effects on soil organic nitrogen and mineral nitrogen content.Sand content and temperature have negative effects on soil organic nitrogen and mineral nitrogen content.