若尔盖盆地不同退化阶段草甸土壤含水率、pH及电导率的变化

Study on Soil Moisture Content, p H and Electrical Conductivity Characteristics at Different Stages of Degraded Meadow in Zoige Alpine Basin

为了更好的了解若尔盖高寒草甸不同演替类型下土壤含水率、pH 值、电导率的变化规律，采用 SPSS、GIS 与 GS＋地统计软件，对若尔盖高寒盆地逆向演替序列中“沼泽草甸-草原草甸-退化草甸-沙化草甸”4种演替阶段不同深度土壤的含水率、pH 和电导率进行了比较和空间格局分析，以期为若尔盖盆地草甸退化和沙化治理及研究提供科学依据。结果表明，（1）各演替阶段土壤含水率随土壤深度的增加而不断降低，草原草甸水分含量由51.04%逐渐下降到33.66%，相比其他3种草甸下降幅度最大（17.38%）；随草甸退化的加剧，草甸土壤各层含水率呈不断下降的趋势，pH 值和电导率呈不断上升的趋势。（2）4个演替阶段草甸土壤含水量范围分别为：沼泽草甸33.66%-51.04%，草原草甸17.92%-23.07%，退化草甸18.00%-20.98%，沙化草甸14.49%-16.83%；4个草甸土壤pH变化范围分别为：6.44-6.74、7.19-7.51，7.52-7.81和29.09-37.21；随退化演替的进行，草甸土壤也由沼泽草甸的酸性土壤逐渐演变为碱性土壤。（3）4种演替阶段草甸土壤3种指标的空间变异，除退化草甸土壤电导率主要受随机性因素影响外，其余均受结构性因素影响，沼泽草甸土壤电导率以及沙化草甸含水率和电导率在结构性因素影响基础上，还叠加了随机性因素的影响。（4）4种演替阶段草甸土壤的3种指标的空间分布，除退化草甸土壤电导率呈破碎斑块状分布外，均表现为连续的条带状分布格局。且随退化演替的进行，草甸土壤含水率高值区不断缩小，pH值和电导率高值区呈不断扩大势态。研究显示，若尔盖高寒盆地草甸3种土壤属性的退化演替特征显著，其空间变异以结构性因素为主导，其次为随机性因素，且随机性因素主要影响土壤的电导率。

The research of soil moisture, pH, electrical conductivity properties of Zoige; alpine meadow, can contribute to the study of mechanism of degraded alpine meadow, as well as the protection and management. With methods of SPSS, GIS and GS＋geostatistical analysis, four kinds of retrogressive succession grassland （swamp meadow, steppe meadow, degraded meadow, and desertification meadow） different depth of soil moiture content, pH and conductivity were analyzed and compared by variance analysis and spatial pattern analysis. The results showed that： （1） With the increase of soil depth, soil moisture content gradually reduce and grassland meadow moisture content decreases from 51.04% to 51.04%, compared with other three stages have the biggest decline （17.38%）; Along with the meadow degradation, meadow soil moisture content reduced gradually in each layer, pH and electrical conductivity increase gradually. （2） The scope of soil moisture content of four stages meadow are： swamp meadow 33.66%-51.04%, grassland meadow 17.92%-23.07%, degraded meadow18.00%-20.98%, and desertification meadow 14.49%- 16.83%; Four meadow soil pH range are： 6.44-6.74, 7.19-7.51, 7.52-7.81, and 29.09-37.21; Along with the meadow degradation , meadow soil from acidic soil evolved into alkaline soil. （3） Four succession stage meadow soil characteristic spatial variability is mainly affected by structural factors, and affected by random factors secondly, while the soil electrical conductivity of degraded meadow is affected by random factors only; The soil electrical conductivity of swamp meadow and moisture content and electrical conductivity of Sandy meadow are affected by structural factors and random factors together. （4） The spatial distribution of four meadow soil properties are characterized by continuous distribution pattern, except for the degraded meadow soil electrical conductivity present broken plaque distribution pattern. Furthermore, with the developing of retrogressive succession, the high value area of meadow soil moisture content shrinking, but pH and electrical conductivity high value area is expanding. The results showed that three soil characteristics of zoige; alpine meadow degradation succession significantly and its spatial variation dominated by structural factors, followed by random factors. Moreover, random factors mainly influencing the conductivity of soil.