白三叶入侵对草地早熟禾功能性状及草坪质量的影响

Effects of Trifolium repens invasion on functional traits and turf quality of Poa pratensi

【目的】白三叶入侵会挤占草坪草的生存空间,严重威胁草坪的质量和功能。明晰白三叶入侵对草坪植物草地早熟禾功能性状及草坪质量的影响,可深入了解白三叶入侵机制,为禾本科草坪的建植养护提供理论依据。【方法】以白三叶入侵草地早熟禾草坪为对象,采用样地调查方法考察不同白三叶入侵程度(对照及轻度、中度、重度入侵)下草地早熟禾功能性状及草坪质量的差异,并通过隶属函数法综合评价各入侵程度下草坪质量。【结果】(1)随白三叶入侵程度的增加,草地早熟禾各器官碳含量、叶片建成成本及碳氮比、碳磷比和氮磷比逐渐降低,而比叶面积、各器官氮和磷含量增大。(2)同一入侵程度下,草地早熟禾各器官碳、氮和磷含量均表现为叶大于根和茎,碳氮比和碳磷比表现为根和茎大于叶,而其氮磷比表现为茎和叶大于根。(3)随白三叶入侵程度的增加,草地早熟禾草坪密度、质地、绿度指数和均一性降低,而地上生物量和地下生物量增大。(4)隶属函数法综合评价结果显示,草坪质量以白三叶未入侵时最优,重度入侵时最差,且叶碳含量对草坪质量的影响最大。【结论】白三叶入侵改变了草地早熟禾功能性状,降低了入侵区草坪质量,严重影响了草坪景观和功能。

[Objective]Invasion of Trifolium repens occupies the living space of turfgrasses and has been seriously threatening the quality and function of turfs.Examining the impact of T.repens invasion on the functional traits of Poa pratensis and turf quality is helpful for understanding the invasion mechanism of T.repens and for establishing and maintaining gramineous turfgrass.[Methods]Taking the T.repens-invaded P.pratensis turf as object,the sample survey method was employed to investigate the differences in the functional traits and turf quality of P.pratensis under different degrees of T.repens invasion(control,low invasion,moderate invasion,and heavy invasion),and to evaluate turf quality by the membership function method.[Results](1)With increase in degree of T.repens invasion,the carbon content of P.pratensis organs and the cost of leaf construction,as well as the ratio of carbon to nitrogen,carbon to phosphorus,and nitrogen to phosphorus were gradually decreased,while the specific leaf area and nitrogen and phosphorus content in the organs were increased.(2)At the same invasion level,the carbon,nitrogen,and phosphorus contents in the organs of P.pratensis were higher in leaves than in roots and stems,and the carbon to nitrogen ratio and carbon to phosphorus ratio were higher in roots and stems than in leaves,while the nitrogen to phosphorus ratio was higher in stems and leaves than in roots.(3)The density,texture,greenness index,and uniformity of P.pratensis turf were decreased with increase in T.repens invasion,while the aboveground biomass and belowground biomass were increased.(4)The comprehensive evaluation by the membership function method showed that turf quality was the best without T.repens invasion but the worst under heavy T.repens invasion.Leaf carbon content had the greatest influence on turf quality.[Conclusion]T.repens invasion alters P.pratensis functional traits as well as affects turf quality,landscape,and function.