Geostatistical Analysis on Multi-Scale Variations of Soil Salinity in the Yellow River Delta

In order to explore the distribution of soil salinity and the reasons for its variation in the Yellow River Delta of China, a field survey was conducted at sampling intervals of 0.04, 0.2, 1 and 6 km. These samples were analyzed in the lab to find out soil total salt, organic matter and pH value. Six other environmental factors (including elevation, slope gradient, soil texture, land use type, micro-geomorphology and depth of water table) were supported by spatial database. Based on statistical and geostatistical procedures, the results show that the variations of soil salinity have three scales and are influenced by different environmental factors. At a narrow scale (sampling intervals are 0.04 and 0.2 km), the soil salinity has small spatial dependence, because it is mainly influenced by pH value which had no structure; at a broad scale (sampling interval is 6 km), the distributions of salinity show a strong structure, because they are impacted by elevation and land use type which have high spatial dependence.