黄河三角洲地区浅层地下水与耕层土壤积盐空间分异规律定量分析

为研究黄河三角洲地区地下水作用条件下耕层土壤的积盐规律，运用GIS和地统计学的原理与方法，结合地下水埋深的空间分布以及临界埋深的划分标准对研究区域进行分区，并从空间尺度对各分区地下水矿化度与耕层土壤积盐规律进行了定量分析。结果表明：地下水埋深、矿化度和耕层土壤盐分均属于中等变异强度，在东西方向和南北方向上均具有2阶的趋势效应；受结构性因素和随机性因素的共同作用，地下水埋深呈中等的空间自相关性，地下水矿化度与耕层土壤盐分呈弱空间自相关性；耕层土壤盐分与地下水矿化度的空间分布具有一定的相关性，与地下水埋深呈负相关性。对空间尺度上的地下水矿化度与耕层土壤盐分定量分析结果表明，耕层土壤积盐与地下水矿化度呈极显著的相关关系，而地下水埋深增加使其相关性减弱，采用分区研究法使地下水矿化度对耕层土壤积盐规律分析更加客观准确。该结果对研究黄河三角洲地区土壤盐渍化的发生机理以及预测与评估该地区土壤盐渍化的发生发展具有重要意义。

Quantitative analysis of spatial distribution pattern of soil salt accumulation in plough layer and shallow groundwater in the Yellow River Delta

In order to study the regularity of soil salt accumulation in plough layer caused by groundwater in the Yellow River Delta, GIS and the fundamentals and methods of geostatistics were applied to regionalize the study area based on the spatial distribution pattern of groundwater table and the criteria of critical water table. And for each sub-region, quantitative analysis was performed between groundwater mineralization and soil salt accumulation in plough layer at the spatial scale. Results indicate that groundwater table, groundwater mineralization and soil salinity in plough layer all exhibite moderate spatial variation, and the trends are all second order in both east-west and north-south directions. Owing to compound impact of structural and stochastic factors, groundwater table exhibites moderate spatial autocorrelation while the spatial autocorrelation of groundwater mineralization and soil salinity in plough layer are both weak. The distribution pattern of soil salinity in plough layer is positively correlated with that of groundwater mineralization to some extent, while it is negatively correlated with that of groundwater table. The quantitative analysis of groundwater mineralization and soil salinity in plough layer, which is performed at the spatial scale, show that soil salt accumulation is significantly correlated with groundwater mineralization while this correlation decreases with the increase of groundwater table, and the regularity analysis of soil salt accumulation in plough layer and groundwater mineralization would be more objective and accurate when sub-regions are adopted. The research results are of great significance for the mechanism, prediction and evaluation of the occurrence and development of soil salinization in the Yellow River Delta.