The Impact of Solifluctions in Daronagar River basin on Physical and Chemical Properties of Soil

Solifluction is the displacement of mud crust on surface of fixed foundation that occurs in areas near glaciers and mountains, which is underestimated as a natural disturbance factor and its ecological role in maintaining biodiversity is ignored. This process affects the denudation of mountains less than fast processes (landslides) and geochemical transitions, but due to its extent, has a great impact on the evolution of mountain landscapes. In order to investigate the physical and chemical properties of different solifluction soils, 4 sites were selected in the Daronagar River basin, located in the north-east Iran, based on the lobe or terrace type. Then, sampling was done from different microtopography, including the riser, tread and ridge parts. Texture, organic carbon, available phosphorus and potassium, pH, electrical conductivity, equivalent calcium carbonate, saturated moisture, soil stability, and porosity were then measured. The results showed that the impact of investigated factors on soil porosity and available phosphorus was not significant. In other studied characteristics, only the simple effect of the type of the studied site was significant. The values of pH, electrical conductivity, saturated moisture, and available potassium in Sites 1 and 2 were lower compared to the other two sites and there was a significant difference. This trend was the opposite in terms of organic carbon, soil stability and equivalent calcium carbonate. The highest value of these parameters was observed in terrace-type solifluctions. It seems that the impact of soil displacement in all types of solifluctions, as well as mutual relationship of some soil characteristics and their effect on each other caused the emergence of different characteristics in the investigated solifluctions.