In recent years, the increasing use of mulching in agricultural practices has been driven by its benefits in weed suppression, soil moisture retention, and improved soil structure. However, Korean farms typically perform mulching and soil covering separately, leading to excessive labor requirements. To address this issue, this study analyzes the safety of a newly developed mulching and soil covering machine. To evaluate its structural safety, strain gauges were attached to critical points of the machine, and strain data were collected under various Power Take-Off (PTO) and engine speed conditions. The measured strain was converted into von Mises stress and maximum shear stress, and the safety factor was calculated using the maximum shear stress theory and the strain energy theory. Additionally, fatigue life was predicted using the rainflow counting method, the Goodman equation, and Palmgren-Miner's rule. The results indicate that the safety factor ranged from 1.65 to 16.54 based on the maximum shear stress theory and 2.42 to 19.83 based on the strain energy theory, confirming that the machine can withstand operational loads without failure. Furthermore, fatigue life prediction revealed that the lowest estimated fatigue life is 14,575 h, equivalent to approximately 607 years of continuous use. These findings demonstrate that the developed machine possesses high safety, making it a viable solution for improving efficiency in mulching and soil covering operations.

Relevance. The increasing recreational load on the ecosystems of the Lake Teletskoe basin, its related obvious damage and the necessity to quantify the ongoing transformations. Aim. To assess the current state of a soil cover of the adjacent territory of Lake Teletskoe in terms of tourism and recreation impact. Methods. Comparative geographical and chemical as well as soil-ecological monitoring of studied indicators of early, short- and long-term diagnostics. Results and conclusions. Because of the tourist activities in the coastal zone of the mountain-forest belt of Lake Teletskoe, a developed path network transforming its natural ecosystems appeared. Some parameters of soil properties and composition on this path and in the sites not affected by recreation differed significantly. The analysis of water extract showed the decrease in acidity, the reduced content of ammonium and nitrate nitrogen, phosphates, a change in the concentration of calcium cations, potassium and magnesium in the top soil layer on the path, as compared to the undisturbed places. Soil trampling by recreants has damaged litter, decreased its thickness or completely destructed the promenade area. Reduction in litter reserves on the moderately developed paths exceeded by more than 2.7-4.0 times, whereas on the well-defined ones (as in the Altai State Biosphere Reserve with the established systemized movement across the territory), litter was absent at all on a few or even single paths. On weakly developed (fresh) paths, litter reserves turned out to be even higher than on the undisturbed areas or on the paths located next to a gravel site. Recreational loads were responsible for the 1.2-1.7 times increase in soil density of the upper (0-5 cm) layer, accompanied by a decrease in soil porosity and air supply. The hardness of soil was 1.3-1.5 times higher on the path than around it. The tourist effect on general physical properties of soil was traced to a depth of 20-30 cm, but maximum changes were noted in its upper (0-5 cm) layer. Recreational loads did not impact essentially on the aggregate soil composition. No significant changes, caused by tourist and recreational activities, were found in the elemental chemical composition of soils. The content of nutrients and lead were within the background and did not exceed the standardized values. The detected high concentrations of arsenic were not associated with the influence of tourist and recreational activities.

This study was conducted to explore the use of non-expansive soil as protective cover for expansive soil slopes. Laboratory model experiments were carried out on expansive soil systems with varying thickness of non-expansive soil cover. The models were subjected to three wet-dry cycles. Variation in soil moisture content was monitored using moisture probes. Surface and internal cracking of soil was observed using cameras. Variation of infiltration rate of the cover with wet-dry cycles was measured in-situ. Results of the study show correlation between cover thickness and evaporation rate and crack formation in the expansive soil. Crack size, quantity, depth, and interconnectivity in the expansive soil increased with decreasing cover thickness. Even the thinnest cover significantly reduced the the number and depth of cracks. The infiltration rate of the cover remained unchanged after three cycles wet-dry cycles. The final water content, after the third drying, in the expansive soil increased with increasing cover thickness.