Polar soils under different vegetation cover from Livingston Island (Antarctica) were studied analyzing indicators of carbohydrates decomposition in soils: organic carbon, biomass carbon, total nitrogen, C:N ratio, cellulase, amylase, and invertase activity. The highest values of microbial biomass in soils were indicated for sites with vegetation cover while the lowest values in soils without vegetation, which correlate with the content of total organic carbon and the C:N ratio. The highest percentage of biomass carbon compared to the total organic biomass carbon is obtained for two sites with mosses, and the lowest in sites without vegetation, followed by the sites with lichens. Cellulase activity is highest in polar soils with moss cover. Amylase activity depends more strongly on the type of vegetation. The highest amylase activity is detected in soils under algae cover and the lowest in soils without vegetation. Invertase activity is limited by the extreme soil and climatic conditions of Antarctica. A very strong, positive correlation is found between total carbon and total nitrogen. The relationship between total carbon and the C:N ratio, as well as between biomass carbon and amylase activity, is moderate, and positive. The higher dependence of amylase activity from organic carbon with microbial origin correlates with higher values of the enzyme amylase compared to the enzyme cellulase. There is a strong (cellulase) and very strong (amylase) positive relationship between the activity of enzymes and the combination of factors: total carbon, total nitrogen, C: N ratio and biomass carbon.

Microbiological indexes have been studied in dynamics at lime treatment and independent planting of lavender (Lavandula angustifolia, variety “Hemus”) and sweet basil (Ocimum basilicum, variety “Genovese”) of fresh sludges from a purification plant, with concentrations of quicklime: 10%, 20% and 30% for a 40-day period of composting. The microbiological analysis includes determining of nonpathogenic (non-spore forming bacteria, bacilli, actynomycetes, micromycetes, bacteria, which assimilate mineral nitrogen) and pathogenic (Salmonella spp., Escherichia coli and coliforms, Enterococcus, Clostridium perfringens) microflora. Out of the beneficial microflora in the sludges the quantity of the non-spore forming bacteria is the biggest, and the lowest is of the actynomycetes. A basic share in the composition of the pathogenic microflora occupies Clostridium perfringens, followed by Escherichia coli and coliforms, and Enterococcus. Absence of Salmonella spp. was established in the studied sludges. The best results for the disinfection of the sludges displays the adding of 30% quicklime (followed by the variants with 20% and 30% lime), on 5-th day of the experiment setting. The pH decrease in the period of the study leads to a repeated development of pathogenic microflora. In the meantime the creation of an alkaline medium leads to decrease in the quantity of the beneficial microorganisms. The decrease of the moisture and the drying of the sludges for the study period display a weaker effect on the dynamics of the microflora in comparison with the pH increase impact. The planting of lavender and basil independently in the sludges samples from a purification plant has a beneficial effect (a little bit better with the lavender variants) for increase of the quantity of nonpathogenic microbes and pathogens frequency of occurrence decrease. The effect is intensified by increasing the plant development period.

A complex of soil carbon properties was studied and a research was made about the content of soil organic matter and organic C. The surface A and Bw horizon of Cambisols were studied in order understand relations of soil organic content and composition. Sample soil profiles in the middle part of Vitosha Nature Park were taken under different type of trees. Higher amount of total carbon and free low-molecular humic acids were determined in the surface and in the cambic horizons. The amount of soil organic carbon is high – from 2.08 % to 5.44 % in the surface horizon. The fulvic-humic type of soil organic matter predominates in studied soil horizons. Similar to this most of the soil samples have ration C/N > 15 which is Mull humus. This type is commonly associated with temperate forest ecosystems, where deciduous trees shed their leaves annually, and contributing organic matter to the soil.

Проведено е сравнително проучване на коренова и почвена микробиологична активност при самостоятелно и съвместно отглеждане на зеле с други култури: праз, фасул, тагетес, копър и цветен микс. Взаимното отглеждане на зеле и цветен микс повишава количеството на микроорганизмите в непосредствена близост до корените на зелето в най-висока степен. Най-ниска е биогенността на кореновата зона при варианта със зеле и тагетес. При самостоятелното отглеждане на зеле се установява по-висока стойност на общата микрофлора спрямо вариантите с основна култура зеле и допълнителни култури тагетес или праз. Комбинирането на зелето с цветен микс, фасул или копър повишава количеството на микроорганизмите от ризоплана и ризосферата в по-висока степен отколкото самостоятелното отглеждане на зеле. Основен дял в състава на общата микрофлора заемат неспорообразуващите бактерии, следвани от бацилите. Прегрупиране се установява при съвместното отглеждане на зеле и цветен микс, като при този вариант количеството на спорообразуващите бактерии е по-високо от това на неспорообразуващите бактерии. По-слабо представени са актиномицетите и плесенните гъби. Каталазната активност е най-висока при контролата, следвана от варианта със съвместно отглеждане на зеле и праз, а най-ниска при зеле и цветен микс, и зеле и копър, като зависи значително от влажността на вариантите. Целулазната активност е по-висока при вариантите с култури спрямо контролата – най-висока при съвместно отглеждане на зеле и праз, и зеле и тагетес, а най-ниска при зеле и фасул, като зависи значително от общата микрофлора.

Microflora composition and antibacterial effect against Escherichia coli of plant extracts from different parts of Lavandula angustifolia and with different solvents were analyzed to determine variants to be used as microbial additives for enrichment with beneficial microflora, decontamination and deodorization of composts contaminated with E. coli. The highest total quantity of microorganisms was found in the decoction variant (whole plant and roots), and the lowest in the tincture variant (whole plant). The quantity of non-sporulating bacteria predominates in most variants. A significant increase of actinomycetes was found in the tincture and medical vinegar variants. The acidification of the environment leads to an increase in the quantity of mold fungi in the medicinal vinegar. Antibacterial effect against Esherichia coli for three tested strains (NMIMCC 3397 (WDCM 00012; ATCC 8739), NMIMCC 3398 T (WDCM 00090; ATCC 11775), NMIMCC 8905 (ATCC 35218)) was similar for the individual plant parts and the same for variants with whole plants. Lavender extracts, medicinal vinegar variant (individual plant parts and whole plant), as well as a decoction variant with a whole plant, showed stronger antibacterial activity against Escherichia coli. The concentration of all parts of the plant in "whole plant" extracts increased antibacterial activity compared to extracts with a concentration from a single specific part of the plant (roots, leaves, stems). Antibacterial activity against Escherichia coli remained lower even when whole plant was used for medicinal wine and medicinal oil variants. The choice of solvent probably has some effect on the diameter of the growth inhibition zone. The addition of Lavender extract (decoction variant, whole plant) to compost variants increased the quantity of non-pathogenic microflora in them. At the same time, the composts were decontaminated from the presence of Escherichia coli. The composts smelled of soil and lavender. The antibacterial effect of the lavender extract (decoction variant) against Escherichia coli strongly positively depends on the quantity of non-pathogenic microflora in it and in the composts after its application. The studied lavender plant extracts (best variant decoction, whole plant) can be applied as microbial additives, disinfectants against Escherichia coli and deodorizers of composts.

Ocimum basilicum L. and Thymus vulgaris L. are natural plant sources of antimicrobial activity, which is essential to determine their qualities as biological agents against pathogenic microorganisms. The aim of the study is the analysis of the antibacterial activity of plant extracts of basil and thyme against Escherichia coli for their subsequent application in agricultural practice as additives for decontamination and deodorization of compost-like mixtures. Plant extracts from roots, stems, leaves and whole plants of basil and thyme were obtained by various methods: decoction, tincture, medicinal vinegar, medicinal wine and medicinal oil. Agar diffusion method was used to determine the antimicrobial activity of the extracts against Escherichia coli. The analyzed essential oil cultures increase the microbiological and enzymatic activity of soils. Basil extracts showed stronger antimicrobial activity against Escherichia coli than thyme extracts, differing for individual plant parts - roots variants showed higher antimicrobial activity compared to variants with leaves, stems and whole plant. In general, a lower antimicrobial activity of the plant extracts was found in the medicated wine and tincture variants (except for roots tincture), compared to the decoction, medicated vinegar and medicated oil variants. The antibacterial activity of the stem extracts depended significantly, and that of the root, leaf and whole plant extracts moderately, on the biogenicity of the soils. The analyzed essential oil cultures can be applied for decontamination (against Escherichia coli) and deodorization of compost-like mixtures. The use of basil and thyme extracts decontaminated composts from E. coli content in a repeated 4-month application.