祁连山南坡微地形下典型生态系统土壤蓄水能力差异

Differences in Soil Water Storage Capacity of Typical Ecosystems Under Microtopography in Southern Slope of Qilian Mountains

[目的]探讨祁连山地区微地形形态下典型生态系统土壤蓄水能力差异性,为该区进一步提高水源涵养能力提供参考。[方法]以微地形不同坡向青海云杉和高山草地为研究对象,采取野外采样和室内试验分析相结合的方法,研究不同坡向对典型生态系统土壤蓄水能力的影响。[结果](1)微地形高山草地所在阳坡区域,土壤水分贮存量随坡位上升逐渐呈减少趋势,坡中上(PZS)为土壤水分贮存量最低的坡位;坡位对土壤饱和蓄水量影响较小。(2)坡位显著影响着阴坡青海云杉土壤水分贮存量,土壤贮水量沿坡位上升呈增加趋势,坡顶处(PSD)土壤水分贮存量最高;坡位对青海云杉土壤潜在蓄水能力影响显著,坡中和坡中上土壤潜在蓄水能力最强。(3)两类典型生态系统土壤蓄水能力存在显著差异,高山草地(阳坡)土壤实际蓄水能力在不同坡位均高于青海云杉,青海云杉(阴坡)土壤潜在蓄水能力在坡位和土层尺度均显著大于高山草地(阳坡)。[结论]研究区微地形坡中上至坡顶段是该区保水增蓄的重点区域,坡中上以下区域是两类生态系统土壤蓄水能力核心区域,应继续保护。

[Objective]The aims of this study are to explore the variability of soil water storage capacity of typical ecosystems under microtopographic morphology in the Qilian Mountains,and to provide reference for further improvement of water holding capacity in the study area.[Methods]Qinghai spruce and alpine grassland distributing on different slope orientations of microtopography were taken as the research objects.A combination of field sampling and laboratory experiments was conducted to study the effects of different slope orientations on the soil water storage capacity of two typical ecosystems.[Results](1)Soil moisture storage was gradually decreasing in the microtopographic sunny slope(alpine grassland)area along the rising slope,with the lowest soil moisture storage in the upper middle of the slope.The slope position has less influence on soil saturation water storage capacity as the potential water storage capacity of the soil.(2)The slope position also significantly influenced the soil water storage capacity of the shaded slope(Qinghai spruce),and the soil water storage capacity increased along the slope position,with the top of the slope being the slope with high soil water storage capacity.The potential water storage capacity of Qinghai spruce soils was significantly affected by slope position,and the potential water storage capacity of soils in the middle and upper slopes was significantly higher than that of other slopes.(3)There were obvious differences in the soil water storage capacity of the two typical ecosystems.The actual water storage capacity of the alpine grassland(sunny slope)soil was higher than that of Qinghai spruce at different slope positions,while the Qinghai spruce(shady slope)soil potential storage capacity at different slope positions was higher.The water capacity was significantly greater than that of the alpine grassland(sunny slope).[Conclusion]Enough attention should be paid to the work of soil and water conservation in the area from the middle to the top of the micro-topographic slope in the study area.The slopes below of upper slope are the key areas of soil water storage capacity of the two types of ecosystems in the micro-topographic.The areas from the middle to the down of the micro-topographic slope are the core areas of soil water storage capacity of the two types of ecosystems.