Peculiarities of Experimental Assessment of Soil Erodibility

Abstract

The erodibility of model soils has been studied using the methodology of washing out soil samples with a water flow in a hydrodynamic tube. Compared to the traditional method of vertical loading of cartridges, the new method of forming soil samples using horizontal loading has made it possible to obtain a more homogeneous resistance of samples during their erosion with the water flow; the layers of soil aggregates were formed perpendicularly to the water flow. The use of the Poseidon measuring device has made it possible to obtain erosion rates in real time, evaluate the quality of sample preparation, and analyze the data for their rejection, in particular, at the beginning and end of the experiments. In addition, the use of the device has allowed us to skip some operations needed to clarify the data of the experiments at their early termination (the consideration of the remainder of a sample, which requires its drying to determine the amount of eroded soil by the mass difference). The data files generated by the device at the end of the experiments significantly simplified their processing and considerably reduced the required time. The coefficient of variation in the erosion rate decreased by an average of 12% using the new method of sample preparation compared to the traditional one. Moisture ranges with minimum erodibility have been established for model soils. The dependences of the soil erosion rate on the water flow velocity in the range of 0.5–2.5 m/s have been demonstrated. The results confirm the correlation of the soil erosion rate with the cube of flow velocity. Soil erodibility was determined as the coefficient of proportionality between the soil erosion rate and the cube of flow velocity. The maximum erodibility coefficient is typical for agro-gray soil (179 × 10^–6), while the minimum value was determined for agrochernozem (53.0 × 10^–6 s²/m²). Agro-sod–podzol soil is characterized by an intermediate value of the erodibility coefficient: 80.3 × 10^–6 s²/m². The proposed methodological approaches and the experimental results can further be used to estimate the erodibility of soils and grounds and model samples with a polyfractional composition close to the natural one.