Effects of selected pesticides and organic substrates onlong-term respiration of soil microbial community

Using of pesticides and plant protection product could cause negative changes in soil microbial communities, despite it is not the primary intent if its application. Soil respiration is an important indicator of microbial metabolic activity. A characteristic respiration curve is obtained from long-term monitoring of CO2 production from soil. Effect of pollutants on activity and growth of soil microorganisms could be determined from parameters and profile of that curve. The aim of our study was to investigate the effect of selected fungicides on soil respiration and organic C mineralization. In the laboratory experiment sandy loam arable soil was spiked by fungicides and cultivated at 20C. Two types of fungicides – dinitrophenol fungicide dinocap and dithiocarbamate mancozeb – were applied to the soil in recommended and 10 times higher doses. Respiration activity was measured as CO2 evolution using the OxiTop system. The influence on substrate induced respiration (SIR) after addition of glucose as available organic in the first 48 hour were compared with 5 days long term respiration kinetic of soil samples. Mineralization of organic carbon was assessed as evolution of CO2 after addition of lucerne meal to the soil sample during 5 days. Respiration kinetic was assessed and parameters of respiration curves were evaluated and compared between spiked and control samples.