A study of soil dispersivity in Qian'an, western Jilin Province of China

Abstract

Saline soil is vulnerable to water erosion because of its dispersivity. This characteristic has a great influence on dam and slope engineering. There is a large area of saline soil in western Jilin Province, the seasonal frost zone, and this soil is highly dispersive. We studied the properties of soil samples collected from vertical holes near Qian’an Dabusu Lake, assessing the particle size distribution and the chemical components. We also comprehensively identified the level of soil dispersivity by three standard methods, the pinhole test, the crumb test, and the double-hydrometer test. The soil composition and basic physicochemical properties are proved to be the most important factors which determine the dispersion degree of the saline soil. Our results showed that, within depth ranges from 0 to 1 m, silt particles highly influenced the soil dispersivity, and the total soluble salt accounted for ≥0.3%. At the first sampling point, in a tall soil column, the dispersion degree decreased with increasing depth, but this was not as obvious at the second sampling point, which was in a flat area. Nevertheless, the superficial soils of these two sampling sites were strongly dispersive, which must be taken into consideration for soil engineering in this region.