Microbiological Nitrogen Transformations in Soil Treated with Pesticides and Their Impact on Soil Greenhouse Gas Emissions

Research was conducted in connection with the pressure exerted by man on the environment through the use of pesticides. The aim of the study was to assess the impact of pesticides on soil and to evaluate the effect of these changes on greenhouse gas emissions into the atmosphere. The research was carried out on soil sown with oilseed rape. The activity of protease and urease, ammonification, nitrification in soil, as well as CO2 (carbon dioxide) and N2O (nitrous oxide) gas emissions from soil were assessed. The analyses were carried out directly after harvest and 2 months after. Pesticides most frequently negatively affected the tested parameters, in particular enzymatic activities. Of the two herbicides used, Roundup had a stronger negative impact on microbial activity. The application of pesticides, especially the fungicide, resulted in an increase in gas emissions to the atmosphere over time. Pesticides disturbed soil environmental balance, probably interfering with qualitative and quantitative relationships of soil microorganism populations and their metabolic processes. This led to the accumulation of microbial activity products in the form of, among others, gases which contribute to the greenhouse effect by escaping from the soil into the atmosphere

Soil Microbial Functional and Fungal Diversity as Influenced by Municipal Sewage Sludge Accumulation

Safe disposal of municipal sewage sludge is a challenging global environmental concern. The aim of this study was to assess the response of soil microbial functional diversity to the accumulation of municipal sewage sludge during landfill storage. Soil samples of a municipal sewage sludge (SS) and from a sewage sludge landfill that was 3 m from a SS landfill (SS3) were analyzed relative to an undisturbed reference soil. Biolog EcoPlatesTM were inoculated with a soil suspension, and the Average Well Color Development (AWCD), Richness (R) and Shannon-Weaver index (H) were calculated to interpret the results. The fungi isolated from the sewage sludge were identified using comparative rDNA sequencing of the LSU D2 region. The MicroSEQ® ID software was used to assess the raw sequence files, perform sequence matching to the MicroSEQ® ID-validated reference database and create Neighbor-Joining trees. Moreover, the genera of fungi isolated from the soil were identified using microscopic methods. Municipal sewage sludge can serve as a habitat for plant pathogens and as a source of pathogen strains for biotechnological applications