以天山云杉(Picea schrenkiana)林为对象,分析天山云杉林土壤养分分布特征,并通过主成分分析计算土壤肥力综合指数(IFI),评价不同海拔、林龄和郁闭度条件下土壤肥力水平,旨在为科学管理天山云杉林土壤资源提供理论依据.结果发现:(1)不同海拔天山云杉林0～20和20～60 cm 土层土壤碳、氮含量均表现为 1900～2100 m＞2500～2700 m＞1700～1900 m＞2300～2500 m＞2100～2300 m.其中海拔 1900～2100 m下0～20 cm 土层土壤碳、氮含量均显著高于海拔2100～2300 m(P＜0.05),此海拔下土壤肥力的综合得分最高(0.45),其中63％的土壤肥力达到Ⅰ级(高)和Ⅱ级(较高)水平,表明海拔1900～2100m范围内土壤肥力状况总体较好.(2)土壤碳、氮含量随着林龄的增加呈现增加的趋势,其中0～20 cm 土层土壤碳、氮含量在成熟林和幼龄林或中龄林间存在显著差异(P＜0.05).成熟林土壤肥力综合得分为0.41,其中54％的土壤肥力达到Ⅰ级(高)和Ⅱ级(较高)水平.(3)高郁闭度(＞0.6)条件下天山云杉林0～20 cm 土层土壤碳、氮含量显著高于低郁闭度(0.2～0.4)(P＜0.05),高郁闭度土壤肥力综合得分较高(0.37),其中38％的土壤肥力达到级Ⅰ级(高)和Ⅱ级(较高)水平,但不存在显著差异.总体而言,天山云杉林表层土壤碳、氮含量受海拔、林龄和郁闭度的影响较显著,土壤肥力指数则受海拔、林龄的影响显著.
Effects of altitude,stand age,and canopy density on soil fertility in Picea schrenkiana forest
The distribution characteristics of soil nutrients in Picea schrenkiana forest were analyzed,and the com-prehensive index of soil fertility(IFI)was calculated through principal component analysis to evaluate soil fertility levels under different altitudes,stand ages,and canopy densities,with the aim to provide a theoretical basis for sci-entific management of soil resources in Picea schrenkiana forest.The results showed that:(1)soil carbon and nitro-gen contents in 0-20 and 20-60 cm soil layers in Picea schrenkiana forest under different altitudes were 1900-2100 m＞2500-2700 m＞1700-1900 m＞2300-2500 m＞2100-2300 m.Soil carbon and nitrogen contents of 0-20 cm at the 1900-2100 m were significantly higher than those of 2100-2300 m(P＜0.05).The IFI under this altitude was the highest(0.45),of which 63％of sampling plots reached grade Ⅰ(high)and grade Ⅱ(relatively high)in soil fertility,indicating that soil fertility was generally good in the range of 1900-2100 m.(2)Soil carbon and nitrogen contents showed an increasing trend with increasing stand age,with significant difference(0-20 cm soil layer)among mature forest,young forest,and middle-aged forest(P＜0.05).The IFI of mature forest was 0.41,of which 54％of sampling plots reached grade Ⅰ(high)and grade Ⅱ(relatively high)in soil fertility.(3)Under the condition of high canopy density(＞0.6),soil carbon and nitrogen contents in 0-20 cm soil layer was significantly higher than those under the condition of low canopy density(P＜0.05),the IFI under high canopy density was higher(0.37),and 38％of sampling plots reached grade Ⅰ(high)and grade Ⅱ(relatively high)in soil fertility,but there was no significant difference.Taken together,the carbon and nitrogen contents in the surface soil of Picea schrenkiana forest were significantly affected by altitude,stand age,and canopy density,while the IFI was significantly affected by altitude and stand age.
万方数据
维普
