银川平原土壤盐分空间分异及影响因子研究

Spatial differentiation and influencing factors of soil salinity in Yinchuan Plain based on MGWR model

  • 摘要: 以银川平原为靶区,利用采样点实测盐分数据,选取9个与土壤盐分相关的影响因子,结合空间自相关分析和多尺度地理加权回归模型(MGWR),探究土壤盐分空间分布特征及其影响因子的作用尺度与空间分异. 结果表明,银川平原土壤盐分Moran’s I指数为0.314,表现为显著的正空间自相关性及空间集聚特征,总体呈现南低北高分布格局. MGWR模型适用于银川平原土壤盐分影响因子研究. 在作用尺度上,地下水埋深、扩展归一化植被指数和土壤含水率带宽为165,作用尺度最大,其次为高程、土壤pH、坡度、地表温度和地下水矿化度,土地利用强度带宽为43,作用尺度最小. 在作用效果上,地下水矿化度、土壤pH正向作用于土壤盐分,土地利用强度、地下水埋深、扩展归一化植被指数和高程负向影响土壤盐分,地表温度主要为正向作用,占总样本的92.7%,土壤含水率和坡度影响不显著. 显著性影响因素中地下水矿化度回归系数均值为0.384,是影响土壤盐分的最主要因素,其次是土地利用强度、地下水埋深、扩展归一化植被指数、地表温度、高程,土壤pH回归系数均值为0.063,影响最小. 各因子对土壤盐分的影响具有不同程度的空间异质性.

     

    Abstract: Focusing on the Yinchuan Plain, we conducted field measurements of soil salinity at sampling points and selected nine factors related to soil salinity. By combining spatial autocorrelation analysis and the multiscale geographically weighted regression (MGWR) model, we investigated the spatial distribution characteristics of soil salinity and the scale and spatial variation of influencing factors. The results showed that the Moran's I index of soil salinity in the Yinchuan Plain was 0.314, indicating significant positive spatial autocorrelation and spatial clustering, with a general pattern of higher salinity in the north and lower salinity in the south. The MGWR model was suitable for studying the influencing factors of soil salinity in the Yinchuan Plain. In terms of scale, groundwater depth, enhanced vegetation index (EVI), and soil moisture bandwidth had the largest scale of influence at 165, followed by elevation, soil pH, slope, surface temperature, and groundwater mineralization, while land use intensity had the smallest scale of influence at 43. In terms of the effects, groundwater mineralization and soil pH had a positive effect on soil salinity, while land use intensity, groundwater depth, EVI, and elevation had a negative effect. Surface temperature had a predominantly positive effect, accounting for 92.7% of the total samples, while soil moisture and slope had insignificant effects. Among the significant influencing factors, the average regression coefficient for groundwater mineralization was 0.384, making it the most significant factor affecting soil salinity. Land use intensity, groundwater depth, EVI, surface temperature, and elevation followed in importance, while the average regression coefficient for soil pH was 0.063, indicating the smallest impact. Each factor exhibited varying degrees of spatial heterogeneity in its influence on soil salinity.

     

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