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<p><strong>Abstract</strong></p> <p>USLE (Universal Soil Loss Equation) was used as a standard tool for evaluating Slovakia's water erosion risk. Understanding interactions between land cover, land use management, and topographical properties of the land are essential to effectively control soil erosion by implementing best management practices. Two ways for LS factor calculation are recommended for use in practice. The first way is in the computing method based on the USLE 2D software, and the second is the other computing algorithms. Various forms can assess the LS factor but with different results. This article aimed to show the differences in LS factor assessment methods in the Myjava Hills – Sobotište study area, a small agricultural area strongly threatened by water erosion. All in two variants before and after the application of anti-erosion measures (water retention grass ditch). Changes in the LS factor were directly indicated in calculating the long-term average soil loss by water erosion. After applying a complex system of anti-erosion measures, results show a significant reduction of the mean long-term soil loss by water erosion in both comparisons.</p> <p><strong>Keywords:</strong> USLE, LS factor, anti-erosion measures, soil loss</p> <p><strong>Acknowledgement:</strong> This study was supported by PhD student project LABEX. The study was also supported by the VEGA grant agency under the contract numbers VEGA 1/0632/19.</p>

Soil water erosion is one of the most widespread and most damaging processes of degradation in the world. Despite the fact that extensive research on it is carried out by a large number of scientists all around the world, it still occupies a leading position among global threats. Because soil erosion is a complex and quite complicated process, small steps have to be undertaken in order to reach any relevant conclusions. In most cases, in order to simulate soil erosion processes, mathematical models are widely used that are considered useful and helpful tools since the measurement of the erosion of terrain consumes time and space and is impossible in many parts of the world. The aim of the study presented lies in an analysis of elements input into a physically-based erosion model. Those input factors directly influence the model's end results, i.e., the soil erosion processes. The article attempts to define to what extent they affect the model results and soil erosion processes as well. The specific parameters of the soil erosion model, i.e., resistance to erosion and hydraulic roughness, were determined by simulated rainfall experiments. The results identify changes in the parameters input to the final model results together with different initial conditions.

<p>Land degradation caused by anthropogenic activities (deforestation, overgrazing, unsuitable land-use and management practices) negatively influence the well-being of people and also accelerates soil erosion processes. The main evidence for a link between soil degradation and water erosion can be seen in the following elements: increasing rainfall intensity, permafrost thawing, biomass production, tillage, cultivation overgrazing, deforestation/ vegetation clearing, vegetation burning, poorly designed roads and paths to a global extent. Therefore, it is significant to investigate degradation processes in order to point out the possible adverse effects of unsuitable management practices of the landscape in the scale of past and future periods. A future prediction of the development of any processes requires long-term investigation and analysis of the phenomenon predetermined to assess future behaviour. On the contrary, analysis of past processes shows us precipitation patterns and reveals their effect on the generation of degradation processes. The study describes the role of rainfall events on a generation of erosion processes, especially soil water erosion in the catchments located in Poland (Zagożdżonka) and Slovakia (Svacenicky Jarok). A common characteristic of these catchments is the susceptibility to degradation processes, the predominance of arable land and the dominant agricultural use of catchments. In the case of Zagożdżonka catchment (Poland) the modelling period covers the years 1963-2020 with the real measured rainfall events. On the contrary, in the case of Svacenický jarok the future development of degradation processes was analyzed based on the future prediction of rainfall events covering the period 2020-2100 and generated by CLM model (Climate Land Model). In both cases, the simulations were performed using the physically-based EROSION-3D model and three scenarios were created in order to model different land cover, land use, soil types and crops on agricultural land. The first scenario reflects current catchment conditions, the second reflects the best conditions (more forests, fewer pastures and unprotected land) and the third involves worst-case conditions (no protective measures or changes of inappropriate management practices). The results provide insight into the development of degradation processes, illustrate how changes in rainfall patterns affect soil degradation processes in the past and future and take into account different scenarios of management practices together with an analysis of the impact of rainfall events on these processes.</p>

<p>The appearance of the water erosion can be found not only in the small mountainous catchments but also in the agricultural hillslopes. Therefore, there is a growing necessity of monitoring and analyzing the potential changes of the features representing water erosion in space and through time. When it comes to monitoring irregular shapes of grooves and gully in the landscape, various modern surveying techniques could be used. The choice of a suitable method and equipment for terrain monitoring depends on the size of the area, its use, the purpose of the research, sufficient accuracy of measurements, weather conditions, and possibly other factors. The field measurements performed in the period 2014 – 2021 will be presented in this abstract. Field measurements were performed in the Myjava hillslope on the selected erosion gully, where throughout the year 2011, seven small wooden check dams were built. The dams had a stabilization purpose. As a part of monitoring, we focused on the dynamics of changes and development of the gully using various modern monitoring and surveying techniques, such as Global Navigation Satellite Systems (GNSS), Terrestrial Laser Scanning  (TLS), and Unmanned Areal Vehicle (UAV). The process of clogging and deepening of the erosive element was evaluated in the selected profiles.</p><p>Moreover, the possibility of implementing further protective measures on minimizing the erosion process was also evaluated. Simulations with the physical erosion model SMODERP were also used in the evaluation. The results showed that the length of the erosion gully increased during the monitoring period. However, the gully is sufficiently stable. Clogging appeared in the locations where the stabilizing elements occurred in both the bottom and transverse profiles.</p>