Olga Germanovna Bushueva

The study of erodibility of model soils using the methodology of washing out soil samples with a water stream in a hydrodynamic tube has been carried out. In comparison to the traditional method of vertical loading of cartridges, the new method of soil samples formation using horizontal loading allowed to obtain more homogeneous resistance of samples in the process of their erosion by water flow, to which the formed layers of soil aggregates are located perpendicularly. The use of the «Poseidon» measuring device made it possible to obtain washout intensities in dynamics, to evaluate the quality of sample preparation and to analyze the data in order to cull them, especially in the beginning and the end of the experiments. In addition, the use of the device allowed to skip some operations needed to clarify the data of experiments at their early termination (remainder accounting that requires drying to determine the mass of washed out soil by difference). The data files generated by the device at the end of experiments significantly simplified their processing and considerably reduced the time required for it. The coefficient of varia- tion of the washout intensity value decreased by 12% on average when using the new method of sample preparation compared to the previous one. The moisture ranges with minimum erodibility have been established for model soils. Dependences of soil washing intensity on water flow velocity in the range from 0.5 to 2.5 m∙s–1 were demonstrated. The results confirm the correlation of soil washout intensity with the cube of the flow velocity. Soil erodibility was determined as a coefficient of proportionality between the intensity of soil washout and the cube of flow velocity. The maximum erodibility coefficient typical for agrogray soil equals to 179×10–6, and the minimum value obtained for agrochernozem was 53.0×10–6 s2∙m–2. Agrosod-podzol soil features the intermediate value of erodibility coefficient: 80.3×10–6 s2∙m–2. The proposed methodological approaches and obtained experimental results can be further used to assess the erodibility of soil and soil monoliths and model samples of polyfractional composition close to natural.