| 高寒草甸重度退化阶段土壤碳氮磷生态化学计量特征及驱动因素 |
| 摘要点击 1486 全文点击 275 投稿时间：2023-10-18 修订日期：2023-12-27 |
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| 中文关键词 青藏高原 高寒草甸 重度退化 生态化学计量 驱动因素 |
| 英文关键词 Qinghai-Tibet Plateau alpine meadow heavy degradation eco-stoichiometry driving factors |
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| 中文摘要 |
| 深入了解土壤营养状况及平衡关系有助于高寒退化草地的有效恢复和管理. 为了研究草甸重度退化阶段土壤碳、氮、磷营养元素之间的平衡关系,采用实地采样调查、室内分析和数理统计等方法,探讨了三江源地区高寒草甸重度退化阶段土壤碳氮磷含量、储量及生态化学计量变化特征及驱动因素. 结果表明,在重度退化阶段,杂类草植物占据绝对优势地位,土壤C∶N∶P约为32.83∶3.87∶0.67,存在一定的氮限制,土壤碳氮磷含量变异系数排序为：有机碳（1.09）>全氮（0.63）>全磷（0.29）；有机碳含量和碳氮比随草地退化指数（GDI）的增加表现为显著线性下降的趋势,而全磷含量和有机碳储量表现为显著的非线性变化,其中全磷含量表现为显著的平缓U型分布,有机碳储量在重度退化阶段初期下降较为平缓,而当GDI为57.9时,急剧下降. Mantel相关分析结果表明,土壤碳氮比、碳磷比和氮磷比与有机碳含量及储量和全氮储量表现为显著的相关关系. 结构方程模型结果表明,土壤含水量直接影响以及通过植被因子间接影响土壤碳氮磷生态化学计量比,土壤含水量和植被因子（高度、盖度和生物量）是影响土壤生态化学计量的关键环境因子. 研究结果可为高寒草甸重度退化草地的恢复提供科学依据和实践指导. |
| 英文摘要 |
| An in-depth understanding of the soil nutrient status and balance relationship can help the effective recovery and management of alpine degraded meadows. In order to study the balance relationship among soil carbon, nitrogen, and phosphorus nutrients during the heavy degradation stage of meadows, field sampling and investigation, indoor analysis, and mathematical statistics were used to explore the characteristics and driving factors of changes in soil carbon, nitrogen, and phosphorus content, storage, and ecological stoichiometry during the heavy degradation stage of alpine meadows in the Sanjiangyuan region. The results showed that in the heavy degradation stage, miscellaneous grass plants occupied absolute dominance, soil C∶N∶P was approximately 32.83∶3.87∶0.67, and there was certain nitrogen limitation. The coefficients of variation of soil carbon, nitrogen, and phosphorus content were in the following order： organic carbon （1.09） > total nitrogen （0.63） > total phosphorus （0.29）. The organic carbon content and the carbon and nitrogen ratio showed a significant linear decreasing trend with the increase in the grassland degradation index （GDI）, while the total phosphorus content and organic carbon storage showed a significant non-linear change, in which the total phosphorus content showed a significant gentle U-shaped distribution, and the organic carbon storage decreased more gently at the beginning of the heavy degradation stage and then decreased sharply when the GDI was 57.9. The results of Mantel correlation analysis showed that the soil carbon to nitrogen ratio, carbon to phosphorus ratio, and nitrogen to phosphorus ratio showed significant correlation with organic carbon content and storage and total nitrogen storage. The results of structural equation modeling indicated that soil water content had direct effects as well as indirect through vegetation factors, soil carbon, nitrogen, and phosphorus ecological stoichiometry ratios, and soil water content and vegetation factors （height, cover, and biomass） were key environmental factors affecting soil ecological stoichiometry. The research results can provide scientific basis and practical guidance for the restoration of heavily degraded grassland in alpine meadows. |
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