祁连山不同海拔青海云杉林土壤碳氮磷生态化学计量特征

Ecological stoichiometry of soil C,N and P in different elevations of Picea crassipes forest in Qilian Mountains

探究土壤理化特性及生态化学计量比在不同海拔梯度和土壤深度的变化趋势,为祁连山青海云杉林的保护研究提供理论依据和数据支撑.以祁连山大野口流域青海云杉林(Picea crassifolia)林地为研究对象,分别设置4个海拔梯度(2700,2900,3100,3300 m),利用梅花五点法和剖面法采集0~10,10~20,20~30 cm的土壤分层样品,测定不同海拔梯度和土壤深度的土壤有机碳(C)、全氮(N)、全磷(P)含量并分析其生态化学计量特征.青海云杉林土壤C和N随着海拔的升高呈先增加后减小的趋势,P则无明显变化趋势.土壤C∶N随着海拔的升高逐渐增大;C∶P和N∶P在海拔梯度上无明显变化规律.随着土壤深度的增加,土壤C,N,P逐渐降低;不同海拔土壤C,N,P及生态化学计量间存在显著差异(R=0.716,P=0.001),不同土壤分层间差异不显著(R=0.39,P=0.175).青海云杉林有机碳含量高于全国平均水平,全氮有效性高而磷素缺乏;研究区C∶N和N∶P含量主要受土壤全氮的影响,因此在青海云杉林的管理中如何调控土壤全氮显得至关重要.研究结果为进一步研究祁连山青海云杉林C,N,P的作用规律和区域生态安全以及全球气候变化提供基础资料.

The ecological response of soil physical and chemical properties and ecological stoichiometric ratio are investigated for different elevation gradients and soil depths,it can provide theoretical guidance and data support for the protection of Qinghai spruce forest in Qilian Mountain National Park.Taking Picea crassifolia forest in the Dayekou Watershed of Qilian Mountains as the research object,four elevation gradients(2700,2900,3100 and 3300 m)were set respectively,and soil stratified samples of 0~10,10~20 and 20~30 cm were collected by using plum five-point method and section method.The contents of soil organic carbon(C),total nitrogen(N)and total phosphorus(P)in different elevation gradients and soil depths were measured and their ecological stoichiometric characteristics were analyzed.The results show that:Soil C and N increased first and then decreased with the elevation,while P showed no obvious change with the elevation.Soil C∶N content increased with elevation,but C∶P and N∶P had no obvious change in elevation gradient.With the increase of soil depth,soil C,N and P decreased gradually.There were significant differences in soil C,N,P and ecological stoichiometry at different elevations(R=0.716,P=0.001),but no significant differences among different soil layers(R=0.39,P=0.175).Through the study of soil organic carbon,total nitrogen and total phosphorus in Picea crassifolia forest in Qilian Mountains,the content of organic carbon in Picea crassifolia forest was higher than the national average level,the availability of total nitrogen was high but phosphorus was lacking.C∶N and N∶P contents in the study area are mainly affected by soil total nitrogen,so how to regulate soil total nitrogen is very important in the management of Picea crassifolia forest.The results will provide basic data for further study of C,N and P of Picea crassifolia forest in Qilian Mountains,regional ecological security and global climate change.