Influence of Vegetation on the Thermal Balance of Different Soil Types Used for Recultivation

Vascular vegetation experiments were carried out with a universal grass mix (Lolium perenne rosemary 30%, Lolium perenne esquire 25%, Festuca rubra casanova 25%, Festuca rubra gondolin 20%). In this study were used mineral waste with a strong acid reaction and soils from three regions - Sofia, Chelopech and Gorubliane. The soils had different contents of humus, nitrogen, mechanical composition and soil reaction. The plants had the best growth on the soil from Sofia, which had the highest humus and nitrogen content. The differences in fresh and dry weight of above-ground biomass of plants growing on different soils in June and July were much more significant than those obtained in October. Biomass data for the autumn season suggests that higher clay content and higher soil reaction of soil from Gorubliane significantly reduced the amount of bioavailable for plants pollutants fraction. The second part of this paper focuses on measurements and analysis of thermal processes in the active layer. The objectives are to determine the soil thermal properties, heat transfer processes and to use a thermal model, determine soil surface heat flow under atmospheric forcing. This model is validated using soil temperature and micrometeorological data from a field measurements.