Dynamics of microbial populations activities after the application of nicosulfuron

Abstract

When a pesticide gets into soil, it takes part in a number of physical, chemical and biological processes that depend not only on the compound itself, but a number of other factors such as physical, chemical, and biological characteristics of soil and climatic factors. Microorganisms play an important role in pesticide degradation as they are able to utilize the biogenic elements from those compounds, as well as energy for their physiological processes. On the other hand, pesticides are more or less toxic substances that can have adverse effect on microbial populations and prevent their development, reduce their abundance, deplete their taxonomic complexity and create communities with a lower level of diversity and reduced physiological activity. The aim of this study was to analyze post nicosulfuron application dynamics of microbial populations’ activity in the soil. By standard methodology, soil pH value was determined as slightly acid to slightly alkaline, humus and available K content as moderate to high, and available P content as very low to moderate. Microbial abundance (total number of bacteria, number of ammonification bacteria, fungi and actinomycetes) was determined by agar plate method. The application of nicosulfuron in all samples and at both locations has resulted in increased number of bacteria, fungi and ammonification bacteria and reduction of the number of actinomycetes. The highest positive effect on the number of microorganisms was 15 days after treatment with nicosulfuron.