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The effect of different factors and preparation conditions of monofraction samples from the arable horizon of leached chernozem on soil erodibility and its relationship with soil tensile strength (STS) has been studied. The exposure of samples at 38°C reduces their erodibility by two orders of magnitude. The drying of samples, on the contrary, increases their erodibility. It has been shown that erodibility decreases during the experiment. It has been found that the inoculation of soil with yeast cultures (Naganishia albida, Lipomyces tetrasporus) reliably increases the STS value in 1.5-1.9 times. The sterile soil is eroded more intensively than the unsterile soil: at 4.9 and 0.3 g/(m2 s), respectively. The drying of soil followed by wetting to the initial water content (30%) has no significant effect on the STS value in almost all experimental treatments. [ABSTRACT FROM AUTHOR]

The effect of density of monofraction samples from the plow horizon of leached chernozem on the rupture rate of interaggregate bonds in water has been studied. The rupture rate of bonds has been determined in a hydraulic flume by alternating passive phases of 1-5 min in duration, during which the sample occurs under a nonmoving water layer, with short (15-s long) active phases with a water flow in the flume. Samples have also been tested for tensile strength and water infiltration rate. It has been shown that the rupture rate of interaggregate bonds is related by a hyperbolic law to the soil density and by an exponential law to the rate of water infiltration to the soil. The latter relationship varies within a year and, hence, can be used as reliable parameter for predicting the seasonal dynamics of soil erodibility. [ABSTRACT FROM AUTHOR]

The close almost functional relationship of the erosion rate and, hence, the erodibility of model soil samples with the temperature of the water used in the experiments has been shown. This suggests that the rupture of bonds between the particles of eroded soil samples is due to the electrostatic forces appearing between the monomolecular water layers around the adjacent soil aggregates similarly oriented with respect to the soil solid phase rather than to the hydraulic forces. The erosion parameters of the samples also strongly depend on the soil moisture. The lowest erosion rate of the heavy loamy chernozem samples is observed at an initial water content of 22-24%. The erosion rate increases and the variability of the results is reduced with both decreasing and increasing the initial water content. [ABSTRACT FROM AUTHOR]