Analysis of the spatial variability of soil moisture and salinity in Ebinur Lake wetlands,Xinjiang

Abstract

为揭示艾比湖湿地土壤退化程度空间分布特征，在离艾比湖湖滨5~15 km，绕湖一周160 km范围内，以湖心质点为中心，将艾比湖划分为东北、东南、西南、西北4个区域，采用传统统计学和地统计学相结合的方法对表层（0~20 cm）土壤盐分、含水量与pH的空间分异特征进行研究.结果表明：绕湖一周不同区域的土壤盐分均属中等变异强度；土壤含水量在西北部属强变异性，而东北、东南和西南部均属中等变异强度；土壤pH在不同区域内均属弱变异强度.绕湖一周除西北部土壤盐分的半方差理论模型较符合球状模型外，其它区域土壤盐分、含水量和pH均符合高斯模型；受结构性因素影响，不同区域土壤盐分、含水量和pH均具有较强的空间相关性；西南部土壤盐分、含水量和pH的Moran's I系数比其它区域的波动大，表明空间相关性较强.艾比湖湿地常年大风、干旱、缺水及沙化盐化的自然因素与引水围堰、种植耐盐碱植物的人为活动造成了采样区表层土壤盐分、含水量和pH的空间分布多呈现不规则条带状格局.艾比湖湿地土壤以盐土为主，重度盐化土次之，土壤盐渍化日益严重.;Systematic research of soil water and salt is commonly lack in previous studies for the Lake Ebinur, thus in this study, in order to reveal the spatial distribution characteristics of soil degradation degree in the Lake Ebinur wetland, by taking the lake side of a distance to the Lake Ebinur 5-15 km, a circle area of 160 km² as research area. The spatial variability of soil salinity,pH and moisture in the surface layer(0-20 cm) of in the circle sampling area of Lake Ebinur was analyzed by using traditional statistics and geo-statistics. The results indicated that the variation in salinity was moderate in the different directions. The soil moisture in the Northeast, Southeast and Southwest belongs to the medium variation intensity, while the northwest belongs to strong variability. The soil pH of different directions has weak variation. Except that the soil salinity of northwest follows with the spherical model, soil salinity, water content and pH in other different directions were in line with the Gaussian model. Soil salinity, water content and pH of different directions showed strong spatial autocorrelation, which were mainly affected by structural factors. Moran's I coefficient analysis proved that soil salinity in the southwest, water content and pH was stronger in spatial correlation than that in the other directions. The natural factors including winds, drought, water scarcity, desertification, salinization, and human activities including diversion cofferdam, planting drought-resistant and salt-tolerant plants, were contributed to sampling area of Lake Ebinur wetland spatial distribution of surface soil salinity, water content and pH. Soil in the Lake Ebinur wetland is mainly of saline-based type, followed by the type of severe salinization and more serious salinization.