Bioenergy crops such as Miscanthus × giganteus are foreseeable as an alternative source to replace fossil fuel and reduce greenhouse gas emissions. They are also assessed as an environment-friendly solution for polluted, marginal and low-quality agricultural soils. Several studies had been launched on soil organic carbon sequestration potentials of miscanthus culture along with its impacts on restoring soil functionality, most of which focus on the long-term basis of the plant’s cultivation. Nevertheless, information concerning the short term impacts as well as the situation in Czechia is still scarce. In this context, a field experiment was launched in 2017 in a poor-quality agricultural land in the city of Chomutov (North-Western Czechia) to compare the impacts of the perennial C₄ miscanthus with an annual C₃ forage crop (wheat) on the soil carbon stocks as well as enhancing its functionality. Results through the 0–30 cm soil profile examination showed that miscanthus plants played a role in improving the studied soil physico-chemical (bulk density and soil organic carbon concentrations) and biological (Phospholipid fatty acids stress indicator, basal respiration and fluorescein diacetate hydrolytic activity) parameters. The naturally occurring δ¹³C concentrations were used to evaluate the direct plant contribution to the total soil organic carbon (SOC) stocks and revealed considerable miscanthus contribution all over the detected soil layers (1.98 ± 0.21 Mg C. ha⁻¹ yr⁻¹) after only 3 growing seasons. It is thus suggested that the C₄ perennial miscanthus possess remarkable prospects for SOC sequestration and restoring degraded lands.

A wide variety of geographic information system tools and methods was used for pre-dam topography reconstruction and reservoir bottom surveying in two dam reservoirs in the Ohře River, Czech Republic. The pre-dam topography was reconstructed based on archival aerial imagery and old maps. The benefits and drawbacks of these methods were tested and explained with emphasis on the fact that not all processed archival data are suitable for pre-dam topography modeling. Bathymetric surveying of a reservoir bottom is presently routine, but in this study, we used a wide combination of bathymetric mapping methods (sonar, ground penetration radar, and sub-bottom profiler) and topographic survey tools (LiDAR and photogrammetry), bringing great benefits for bottom dynamic analysis and data cross-validation. The data that we gathered made it possible to evaluate the formation of the inflow deltas in the reservoirs studied and assess the sediment reworking during recent seasonal drawdowns. A typical inflow delta was formed in the deeper of the two studied reservoirs, while the summer 2019 drawdown caused the formation and incision of a temporary drawdown channel and erosive downstream transport of approximately 1/10 of the delta body thickness in approximately 1/10 of the delta transverse size. No inflow delta was formed in the shallower of the studied reservoirs, but unexpectedly extensive sediment reworking was observed in the inflow part of the reservoir. Both the studied reservoirs and the pre-dam river floodplain have accumulated historical contamination by risk elements such as As, Hg, Pb; thus, the enhanced erosion of existing sediment bodies expected in the future, owing to more frequent droughts and global climate change, will endanger the ecological quality of the water and solids outflowing from the reservoirs.