The present study deals with the investigation of soil organic carbon in two water catchments in Northern Rila, Western Bulgaria. Field research, combined with analysis, provided sufficient data. Six key sites were selected and sampled in order to estimate and compare the amount of organic and inorganic carbon in the topsoil. The applied criteria for the choice of sites included: vegetation cover, predominant soil group, level of anthropogenization and transport accessibility. A total number of 13 samples from both catchments were collected and analyzed in the Central laboratory of the Institute of Soil Science, Agrotechnologies and Plant Protection (ISSAPP) “N. Pushkarov“. The results concern the amount and composition of soil organic matter in different soils – Cambisols (Albic, Humic, Dystric), Fluvisols and Umbrosols. The total carbon content of all samples varies between 1.23 and 9.69%. The amount of organic carbon ranges between 0.45 and 3.73%. The results of the study prove once again that the preservation of natural vegetation and current condition of the soil is of great importance for carbon sequestration and climate change mitigation.

Block streams, also known as stone rivers, are common periglacial landforms in the alpine and subalpine zone of the Balkan Peninsula. These features are especially widely spread in the valleys, slopes and summit of Vitosha Mountain. The presented research aims to estimate the total area of block streams and perform morphometric analysis of these landforms within the basin of Vladayska River. Block streams are digitized man-ually from orthophotographs and topographic maps using GIS software. Morphometric parameters such as area, length, width, elongation ratio and mean elevation are calcu-lated or extracted from a digital elevation model for each polygon. A linear regression test was conducted to evaluate the relationship between morphometric properties. Results indicate a significant correlation between the area and perimeter (R2 = 0.93) and between the length and width (R2 = 0.94) of the block streams. Block streams are present in the elevation range between 1177 and 2244 m, covering a total area of 169.7 ha. The largest ones occupy the area of Zlatnite Mostove and Yurushki Most, as well as the vicinity of Cherni Vrah Peak. Their length varies from 5–6 m up to 2.2 km, while their width changes from a few meters up to 0.6–0.7 km. Comparisons between block streams from different sites within the catchment area yield new insights into the diver-sity of these landforms. Their dimensions and spatial distribution are key to understand-ing the processes of their formation and evolution.

The following paper represents results from a research focused on the soil associations and their corresponding vegetation communities (soil-plant catenas), located on the northern slopes (N, NW, NE) of the Rila Mountains. Data from eight key sites located between 815 and 2041 m above sea level is discussed. The slope in each site varies from 2° to 25°, and most often the tests and descriptions were carried out on sites with a slope of 10-15°. Vegetation cover is analyzed with plant community plots which provides data on species composition, abundance and coverage. The size of each plot varies from 16 up to 225 m² depending on the vegetation type. Topsoil horizons were tested in each site in order to diagnose the subspecies diversity of brown forest soils (Cambisols) using ratio of humic acids to fulvic acids. That ratio varies from 0,69 up to 1,61 in all studied sites. Both acids are associated with the dominance of different vegetation types – deciduous, mixed or coniferous forest or herbaceous canopy. The results are interrupted in terms of the diagnosis and classification of Cambisols and Umbrosols in the area of interest. Differences in soil and vegetation cover of Northwest and Eastern Rila Mountain are highlighted and analyzed.

In recent years, various regions worldwide have experienced an increase in the frequency and severity of extreme weather events, including cold and heat waves, floods, droughts, forest fires, and storms. Climate models predict that many areas, particularly in Southern Europe, including Bulgaria, will face heightened drought and longer dry periods, along with higher temperatures. Climate change and weather-related disasters profoundly impact agriculture, one of the most important sectors of Bulgaria's economy. This study provides an overview of regional climate change trends in Bulgaria, focusing on extreme weather events such as frost occurrences, hailstorms, thunderstorms, heat waves, and droughts. Increased temperatures and altered precipitation patterns lead to stress on crops such as wheat, maize, and sunflowers, which are critical to Bulgaria’s agriculture. The survey results among Bulgarian farmers show that Bulgarian agriculture is increasingly vulnerable to droughts and climate variability. In addition to drought, Bulgarian farmers report an increase in extreme weather events such as hailstorms, irregular precipitation patterns, and reduced snow cover during winter. Furthermore, the distinction between the four seasons has become less pronounced, with a notably shorter spring season. This research includes a detailed case study on the impact of extreme drought on major crops in Bulgaria. This impact was assessed using a correlation analysis between the Standardised Precipitation Evapotranspiration Index (SPEI), a key drought indicator, and average crop yields. The analysis focused on crops that are highly dependent on moisture availability, such as maize and sunflower, in addition to Bulgaria's primary cereal crop, wheat. The findings indicate that droughts significantly reduce crop yields, especially in regions reliant on rain-fed agriculture. Bulgarian farms are implementing adaptive measures such as adjusting sowing dates and cultivating drought-resistant crop varieties. However, these strategies are not always sufficient to address the challenges posed by climate change, as it remains difficult to predict the alternating patterns of dry and wet years. The results of the study emphasize the importance of continued research, policy support, and investment in adaptation strategies to ensure the resilience of the agricultural sector.