明晰不同区域盐渍化土壤分布特征是精准改良盐碱地的基础，研究宁夏银北灌区土壤盐分空间分布特征，为盐碱地改良提供依据。以宁夏银北灌区为研究对象，采用经典统计学和地统计学方法分析了6.0、1.0、 0.2 km采样尺度下土壤盐分分布特征以及空间变异特性。结果表明，在6.0、1 .0、 0.2 km采样尺度下研究区0~20 cm表层土壤盐分含量整体偏高，且分布不均，差异性较大，变异系数分别为0.927、0.932、1.187，达到中强变异水平；土壤盐分的半方差函数块基比分别为32.653% 、38.462%、41.463%，属于中等强度空间自相关。随着采样间隔的增大，土壤盐分空间自相关性增强，种植、灌溉、施肥等随机因素对土壤盐分空间异质性的影响逐渐减弱，而气候、水文、地形、土壤等结构因素对土壤盐分空间分布的影响不断增强。建议在随机因素影响较大的中小尺度上增大采样量，以深入了解土壤盐分的空间分布特征和变异规律。

Analyzing the distribution characteristics of saline-alkaline soils in different regions is the basis for accurate improvement of saline-alkaline lands. In this study, we analyzed the spatial distribution characteristics of soil salinity in the Yinbei irrigation district of Ningxia, providing a basis for saline-alkali land reclamation. Using the Yinbei irrigation district of Ningxia as the research object, classical and geostatistical methods were used to analyze the distribution characteristics and spatial variability of soil salinity at sampling scales of 6.0, 1.0, and 0.2 km, respectively. The results showed that at the 6.0, 1.0, and 0.2 km sampling scales,the salinity content of the surface soil (0 to 20 cm) in the study area was high and unevenly distributed with large variability, and the coefficients of variation(CV) were 0.927, 0.932 and 1.187, respectively, indicating medium-high level of variability. The half-variance functions of the soil salinity at the three sampling scales were 32.653%, 38.462% and 41.463%, respectively, indicating a moderate spatial autocorrelation. With the increase of sampling interval, the spatial autocorrelation of soil salinity increased. The influence of random factors such as planting, irrigation and fertilization on the spatial heterogeneity of soil salinity gradually weakened, whereas the influence of structural factors such as climate, hydrology, topography, and soilproperties on the spatial distribution of soil salinity was continuously enhanced. It is recommended to increase the sampling volume at small and medium scales, where random factors have a greater influence, in order to gain a deeper understanding of the spatial distribution characteristics and variability patterns of soil salinity.

S159.2

宁夏自然科学基金(2022AAC03458)；宁夏重点研发计划(2023BCF01050)；国家重点研发计划子课题(2021YFD1900605-05)。