高寒地区紫花苜蓿根系吸收资源空间与土壤性质的相关性研究

Correlation and role of alfalfa plant below-ground habitats in alpine regions with plant traits and soil properties

摘要:

【目的】 为明确根系吸收资源空间大小与高寒地区紫花苜蓿植物学性状及土壤理化性质的相关性。【方法】 以青海省海南草原改良试验站种植的紫花苜蓿为研究对象，通过相关回归方程方法，分析各因素和根系吸收资源空间的相关关系，研究高寒草地紫花苜蓿根系吸收资源空间对植物性状和土壤性质的相关性。同时基于路径分析方法，分析土壤理化性质与地上生物量等对高寒草地土壤根系吸收资源空间的影响作用。【结果】 高寒草地紫花苜蓿根系吸收资源空间大小在722. 96~3952. 78 cm³，土壤理化性质（全氮、有机碳、硝态氮）、地上生物量、叶片含水率与根系吸收资源空间存在显著正相关（P＜0. 05），而茎叶比、土壤电导率和pH 与根系吸收资源空间表现出显著负相关（P＜0. 05）；且路径分析发现，土壤水分、pH、地上生物量以及有机碳（TOC）对紫花苜蓿根系吸收资源空间具有较强的直接影响，全氮（TN）通过硝态氮对根系吸收资源空间产生间接作用。【结论】 高寒草地紫花苜蓿根系吸收资源空间的扩展受土壤理化特征与地上生物量等因素综合影响。

Abstract:

【Objective】 To clarify the correlation between the spatial size of root uptake resources and alfalfatraits and soil physicochemical properties in alpine regions.【Method】 Based on the Hainan Grassland ImprovementExperimental Station in Qinghai Province， the study took alfalfa planted in experimental plots as the research object，analyzed the correlation relationship between factors and root absorption resource space through the method of correlationregression equations， and studied the correlation between alpine grassland alfalfa root absorption resource spaceon plant traits and soil properties. At the same time，based on the path analysis method，we analyze the role of soilphysicochemical properties and aboveground biomass，etc. on the space of soil root uptake resources in alpine grassland.【Result】 The spatial size of alpine grassland alfalfa root uptake resources ranged from 722. 96~3952. 78 cm³，and soil physicochemical properties （TN，TOC，NO₃^--N），aboveground biomass， and leaf water content were significantlypositively correlated with the belowground habitat（P＜0. 05），while stem to leaf ratio， soil conductivity，and pH（ P＜0. 01） showed significant negative correlation with the belowground habitat； and the path analysis foundthat soil moisture，pH，aboveground biomass， and organic carbon （TOC） had strong direct effects on alfalfa subsurfacehabitat， and total nitrogen （TN） had indirect effects on root subsurface habitat through nitrate nitrogen（NO₃^--N）.【Conclusion】 In summary，the expansion of alfalfa root uptake resource space in alpine grassland is affected bythe combination of soil physicochemical characteristics and aboveground biomass.