Soil erosion by water causes the loss of soil mineral particles and soil organic carbon (SOC). For determining the effectiveness of soil conservation measures on arable land, rainfall simulations are regularly carried out in field trials in the Czech Republic. The objective of this study was to analyse a dataset from 82 rainfall simulations on bare fallow soils, containing information on slope inclination, soil texture, soil bulk density, SOC, and soil loss with respect to the preferential erosion of fine-grained soil particles and the enrichment of SOC in the eroded soil. Each rainfall simulation comprised a first rainfall period of 30 min and a second one of 15 min in duration. The rainfall intensity was 1 mm min⁻¹ and the kinetic energy of the raindrops accounted for 8.78 J m⁻² mm⁻¹. Runoff samples were taken to determine the soil loss and SOC enrichment in the eroded material. Regression analyses revealed that on sites with 14% slope inclination, soil loss was driven by preferential erosion of fine-grained particles in the first rainfall period. Low soil loss was generally coupled with high SOC enrichment and vice versa, indicating that preferential erosion of SOC occurred mainly in soils with low erosion susceptibility. In order to prevent erosion of SOC and maintain soil quality, soil conservation measures are important in all soil types.

With regard to an increasing intensity and frequency of drought and heavy rainfall, there is a need to adapt arable farming to these climatic changes. In this respect, organic agriculture has a higher adaptation potential than conventional agriculture, since organic farming leads to an enrichment of soil organic carbon and a stimulation of soil biological activity in the long term. As a result, an improvement of soil structure, water infiltration and soil water retention can be expected as compared to conventional agriculture.In April 2023, a study of soil hydraulic properties after 15 years of recognised organic management was commenced in the Czech Republic. The objective is to compare an organic farming system to a conventional farming system in terms of retention of plant available soil water. The hypothesis is that the retention of plant available soil water is higher in the organic farming system than in the conventional farming system.The studied site is a long-term field trial on a clay loam soil in Praha-Uhříněves (P = 584 mm, T = 8.3 °C). In either farming system inversion soil tillage is carried out by mouldboard ploughing to a depth of 20 cm. For either farming system two plots with summer wheat (Triticum aestivum L.) are sampled in 2023 and 2024. In order to analyse soil water retention functions, saturated hydraulic conductivity, and soil organic carbon content, soil samples are taken in 10 cm and 30 cm soil depth each year in spring, summer, and autumn. In order to unravel the sources of plant available water, further soil samples are taken bimonthly in 10 cm, 30 cm, and 45 cm soil depth. The soil water’s isotopic composition (δ2H, δ18O) of these samples is analysed and compared to the rainwater’s isotopic composition. The volumetric soil water content is continuously recorded in 10 cm, 30 cm, and 45 cm soil depth.Preliminary data from the first experimental year indicate that the volumetric soil water content in the organic farming system is higher than in the conventional farming system. In contrast, soil water retention and soil organic carbon content do not show differences between the two systems. However, for robust results with statistical validation, further data and analyses need to be waited for. Therefore, reliable conclusions regarding the hypothesis of a better retention of plant available soil water in the organic system will be possible in the course of the project.This project is funded by the institutional support of the Czech Academy of Sciences (RVO: 67985874) and by the Faculty of Environmental Sciences of the Czech University of Life Sciences Prague (IGA grant No. 2023B0042).

The changes in land cover, particularly in vegetation, directly influence regional water systems through various processes and have potential to alter not only microclimates and local hydrological regimes, but also local ecosystems and downstream water resources. This article investigates the interplay between land cover change and hydrological processes over a 30-year period in the mid-latitude mountainous catchment. Key vegetation trends were identified by supervised classification of geometrically and radiometrically corrected Landsat satellite imagery. Specifically, the replacement of coniferous forests with transitional woodland-shrub and a gradual increase in mixed forests, influenced by disturbance events, such as windthrows and bark beetle outbreaks, were observed. The SWAT model was successfully calibrated and validated using long-term discharge data, allowing for the simulation of land cover scenarios. Results suggest that land cover changes exerted a limited influence on total water balance, indicating a degree of hydrological resilience of the catchment. However, they affected the partitioning of runoff components, such as direct flow, subsurface lateral flow, and groundwater recharge. The study demonstrates the value of integrating the satellite-based land cover analysis with process-based modelling to understand long-term land-hydrology interactions in complex terrain. The findings underscore the importance of improving spatial resolution, dynamic vegetation modelling, and soil-vegetation parameterization for future assessments under changing environmental conditions. This research contributes to a growing body of knowledge essential for sustainable water resource management in sensitive mountain regions.