云南乌蒙山国家级自然保护区不同植被类型土壤养分特征

Characteristics of Soil Nutrients of Different Vegetation Types in the Wumeng National Nature Reserve,Yunnan

以云南乌蒙山国家级自然保护区6种植被类型为研究对象,分析不同植被类型土壤养分分布特征及供给状况。结果表明:(1)6种植被类型土壤养分整体表现为方竹林较高,次生林和草甸次之,原生林最低,土壤C和K的质量分数较高,N和P的质量分数较低;各植被类型土壤养分及比值变异系数均为中等强度变异,其中,土壤P、K的变异系数小于C、N,土壤w(C)∶w(P)和w(N)∶w(K)的变异系数明显小于w(C)∶w(N)、w(P)∶w(K)。(2)土壤C、N、P、K质量分数及其化学计量比在不同土层、不同植被类型间差异显著(P<0.05)。不同植被类型土壤C、N质量分数整体随土层深度增加而减少;原生常绿阔叶林土壤P质量分数随土层深度增加整体增加,其他植被类型土壤P质量分数随土层深度增加整体逐渐减少;除方竹林和草甸外,其他植被类型土壤K质量分数随土层深度增加而增加。(3)土壤C、N、P质量分数间均存在极显著的正相关关系(P<0.01);不同植被类型土壤养化学计量比在不同土层中变化规律各异,除土壤w(N)∶w(K)外,各土壤养分化学计量比之间差异显著(P<0.05)。因此,云南乌蒙山国家级自然保护区土壤养分质量分数受植被类型影响显著,不同植被类型、土层间养分质量分数及化学计量比具有显著差异(P<0.05),土壤P元素质量分数和w(C)∶w(N)明显低于全国平均水平,土壤N和P质量分数是6种植被土壤的限制因素。

Taking six major vegetation types in the Wumeng National Nature Reserve of Yunnan as research objects,we analyzed different vegetation types soil nutrient distribution characteristics and supplies.The conclusion obtained were as follows:(1)The soil nutrition of six vegetation types showed:Chimonobambusa quadrangularis forest was highest,the second was secondary forests and meadow,primary forest was lowest.The contents of soil C and K were higher,while N and P were lower.The six vegetation types soil nutrient and ratio variant coefficient was medium intensity variation,the P and K variation coefficient was less than C and N,the w(C)∶w(P)and w(N)∶w(K)variation coefficient was significantly less than w(C)∶w(N)and w(P)∶w(K).(2)There was a significant difference(P<0.05)between different vegetation types and soil layers about C,N,P,K with their ratios.In different vegetation types,the contents of soil C and N were decreased with soil layers depth,the original evergreen broad-leaved forest soil P content was increased overall with soil layers depth,but others were decreased,except C.quadrangularis forest and meadow,the soil K fraction of mass was increased with soil layers depth.(3)There was significant positive correlation among soil C,N and P contents(P<0.01);Different vegetation type soil nutrient ratios varies in different soil layers,except for soil w(N)∶w(K),the stoichiometric ratios of soil nutrients were significantly different(P<0.05).Therefore,the vegetation types affected soil nutrient content significantly,there was a significant difference(P<0.05)between different vegetation types and soil layers soil nutrient content,ratio,soil P element content and w(C)∶w(N)were significantly lower than those of average levels of China,and N,P contents were limiting elements of the soil of the six vegetation types.