基于^(31)P核磁共振探究退化高寒湿地土壤磷素演变特征及影响因素  

Evolution of soil phosphorus forms and factors influencing their formation based on ^(31)P nuclear magnetic resonance analyses of degraded alpine wetland

作　　者：罗原骏 蒲玉琳 袁大刚 李亚丽 钱虹宇 LUO Yuan-jun;PU Yu-lin;YUAN Da-gang;LI Ya-li;QIAN Hong-yu(College of Resources,Sichuan Agricultural University,Chengdu 611130,China)

机构地区：[1]四川农业大学资源学院,四川成都611130

出　　处：《草业学报》2024年第2期1-12,共12页Acta Prataculturae Sinica

基　　金：四川省科学技术厅应用基础研究项目(2021YJ0341)资助。

摘　　要：探明高寒湿地不同退化程度土壤磷素组成特征及其形态演变的驱动机制对于湿地生态恢复过程中养分和碳汇的科学管理具有重要意义。以若尔盖自然保护区内相对原生沼泽(RPM)、轻度退化沼泽(LDM)、中度退化沼泽(MDM)、重度退化沼泽(HDM)为对象,采用液相31P核磁共振波谱技术、分段式结构方程模型研究了高寒湿地退化过程中土壤磷素演变特征及主要影响因素。结果表明,高寒湿地退化导致植物群落组成由湿生向中生演替,土壤有机质与氮含量降低。正磷酸盐和磷酸单酯含量随湿地退化呈先增加后降低的趋势,其中正磷酸盐在HDM中相较于RPM降低46.45%,磷酸单酯在LDM、MDM和HDM中相较于RPM分别增加27.02%、54.96%和41.74%;焦磷酸盐和磷酸二酯含量随湿地退化逐渐降低。分段式结构方程模型的拟合结果显示,植被生物量、土壤养分和微生物活性是影响湿地土壤磷素演变的主要因素,其中微生物活性是正磷酸盐、焦磷酸盐和磷酸二酯的正向影响因子,是磷酸单酯的负向影响因子,植物生物量是正磷酸盐和磷酸二酯的正向影响因子,土壤养分虽对各形态磷没有直接影响,但可通过调控微生物活性间接影响焦磷酸盐和磷酸二酯含量。综上所述,湿地退化通过改变植物群落组成、降低土壤养分含量和微生物活性,促进了土壤磷酸二酯分解;重度退化湿地土壤磷有效性因磷酸单酯矿化能力减弱、正磷酸盐含量降低而减小。The aim of this study was to clarify the patterns of soil phosphorus transformation and factors driving this process during alpine wetland degradation.Such information is useful for devising strategies to manage nutrient and carbon“sinks”in the ecological restoration of wetlands.Four types of marsh wetlands in Zoige Nature Reserve,including relatively pristine marsh(RPM),lightly degraded marsh(LDM),moderately degraded marsh(MDM),and heavily degraded marsh(HDM),were selected to investigate the evolution of phosphorus forms in soil,and factors affecting this process.Analyses were conducted using ^(31)P nuclear magnetic resonance and a piecewise structural equation model.It was found that the degradation of alpine wetland led to a succession of plant communities from hygrophytes to mesophytes,and reductions in the soil organic matter and nitrogen contents.The contents of orthophosphate and phosphate monoesters displayed a parabolic trend with the maximum occurring in MDM along the gradient of marsh degradation.The orthophosphate content was 46.45%lower in HDM than in RPM.The phosphate monoesters content was 27.02%,54.96%,and 41.74%higher in LDM,MDM,and HDM than in RPM,respectively.The contents of pyrophosphate and phosphate diesters continuously decreased with increasing severity of wetland degradation.The piecewise structural equation model indicated that microbial activity was a positive factor influencing soil orthophosphates,pyrophosphates,and phosphate diesters,and a negative factor influencing phosphate monoesters.Vegetation biomass was a positive factor influencing soil orthophosphates and phosphate diesters.Soil nutrients indirectly affected pyrophosphates and phosphate diesters by impacting microbial activity.Overall,wetland degradation promoted the decomposition of phosphate diesters by changing the vegetation community and decreasing soil nutrient availability and microbial activity.Soil phosphorus availability decreased in HDM because of the decline in the phosphate monoester mineralization rate and

关 键 词：若尔盖高原 高寒湿地退化 液相^(31)P核磁共振 磷形态 

分 类 号：S153.6[农业科学—土壤学]