Using Portable Field Rainfall Simulator for Experimental Research of Soil Resistance

Abstract

Due to the action of erosion processes, degraded areas of forests have a reduced capacity to perform ecosystem services and a reduced production potential of wood mass. In an attempt to reduce such negative effects, one of the steps is to determine the elements of the mechanisms of erosion processes in order to achieve an appropriate solution for remediation by analysing the physical and mechanical parameters of the soil. Using a portable field rainfall simulator in the forest area in the gullies and the conditionally stable zone of the gullies’ banks, experimental soil testing has conducted. Тhe simulator that was used is based on the pop up sprinkler system described in detail by Živanović et al. (2022). The limited amount of water on the field, as well as the duration of the pouring rain for the study area, affected the duration of each test to be limited to 10 minutes. During the experiment, the effects of changes in soil moisture on changes in the parameters of soil shear resistance and resistance to penetration, as well as the formation of surface runoff and soil erosion, have been observed. Research has been conducted during the spring and autumn. It was established that the change in the current soil moisture affects the change in the mechanical parameters of the soil. Compared to tests on gullies’ banks, the values of soil shear resistance and resistance to penetration are lower in tests in gullies. The presence of cracks and macropores influenced the appearance of rapid infiltration into the soil of part of the precipitation, which resulted in small amounts of runoff water on the exit profile (3.76–32.71% of the total volume of rain). Surface erosion occurs in the form of tearing off entire microaggregates and their transport via micro-furrows to the outlet profile. The concentration of sediments in the water, during tests on the banks, tended to decrease with each subsequent repetition. It’s been determined that soils of the research area are sensitive to erosion processes when they are in a state of low natural humidity. With an increase in water content above 20%, the soil becomes more sensitive to erosion processes and other forms of physical degradation. After an increase in the current water content above 42% (the average value of the liquid limit), the soil was in a saturated state when the resistance forces cease to act.