祁连山中部不同植被类型土壤生态化学计量特征研究

Ecological stoichiometry of soils with different vegetation types in the middle part of the Qilian Mountains

为揭示祁连山中部天涝池流域不同植被类型对土壤碳、氮、磷生态化学计量特征的影响,以天涝池流域青海云杉、祁连圆柏、亚高山灌丛和干草原4种植被土壤为研究对象,探究土壤w(有机碳)、w(全氮)、w(全磷)及其生态化学计量特征.结果表明, 4种植被w(有机碳)、w(全氮)、w(全磷)均随土层深度增加而减小. 0~50 cm土壤中, w(有机碳)表现为青海云杉>祁连圆柏>亚高山灌丛>干草原;w(全氮)表现为青海云杉>亚高山灌丛>祁连圆柏>干草原;w(全磷)表现为亚高山灌丛>祁连圆柏>青海云杉>干草原;土壤w(C)∶w(N)表现为青海云杉>祁连圆柏>亚高山灌丛>干草原.土壤w(C)∶w(P)和w(N)∶w(P)受植被类型的影响,表现为青海云杉>祁连圆柏>亚高山灌丛>干草原.亚高山灌丛、干草原和祁连圆柏土壤均w(N)∶w(P)<10,受N限制,青海云杉土壤w (N)∶w (P)=10~20,受N和P共同限制;土壤碳、氮、磷之间相互影响,土壤有机碳和全氮的变化规律一致,土壤w(C)∶w(P)和w(N)∶w(P)随着土壤w(含水)和土壤w(砂粒)升高呈上升趋势,随容重增大呈下降趋势.

To analyze the effects of different vegetation types on the ecological stoichiometry in the Tianlaochi catchment in the middle part of the Qilian Mountains,four types of soil under Picea crassifolia,Sabina przewalskii,subalpine shrub and subalpine steppe were selected as study objects.w(soil organic carbon),w(total nitrogen),w(total phosphorus)and there ecological stoichiometry characteristics were measured,and the results showed that w(soil organic carbon),w(total nitrogen)and w(total phosphorus)decreased with the increase of soil depth;in the 50 cm soil depth,the order of w(soil organic carbon)inthe four vegetation types was P.crassifolia>S.przewalskii>subalpine shrub>subalpine steppe;the sequence of w(total nitrogen)was P.crassifolia>subalpine shrub>S.przewalskii>subalpine steppe;the order of w(total phosphorus)was subalpine shrub>S.przewalskii>P.crassifolia>subalpine steppe;w(C)∶w(N)ratios of soils were more stable,with the order of the soil w(C)∶w(N)ratio being P.crassifolia>S.przewalskii>subalpine shrub>subalpine steppe.Soil w(C)∶w(P)and w(N)∶w(P)ratios were affected by the vegetation types,their sequences in four vegetation types showed as P.crassifolia>S.przewalskii>subalpine shrub>subalpine steppe.Soil carbon,nitrogen and phosphorus interacted with each other,the change trend being consistent with that of carbon and nitrogen.Soil w(C)∶w(P)and w(N)∶w(P)ratio increased with the increase of w(soil water)and w(sand),and decreased with the increase of the soil bulk density.