Paper Title
Soil Microbial Activity in Maize Crop after Application of Nicosulfuron

Abstract
Nicosulfuron ia a herbicide with a triazine-pyrimidine ring. The special place in the processes of degradation of the herbicide belongs to the soil microorganisms. The aim of this work was to evaluate the influence of different dosage of nicosulfuron herbicide on soil microbial activity in maize crop. Nicosulfuron (ACCENT® DuPont, 750 mg kg−1) was applied to the different plots at three dose levels (x1, x2 and x5 the recommended dose) using a backpack sprayer. Control treatment was a plot where no herbicide was applied. Soil samples were collected before treatment and at 7, 14, 28, 60 and 120 days post nicosulfuron application. Microbial activity in soil under maize crop was influenced by nicosulfuron application. Total number of bacteria initially decreased than increased. The number of ammonifiers decreased by the end of research period. Actinomycetes and fungi adapted after short period of decrease post nicosulfuron application. Most sensitive were azotobacters with decreasaed number throughout the experimental period. The activity of dehydrogenase enzyme was also affected negatively by the application of all three doses of herbicide. Further research is needed to investigate the impact of various herbicide application on soil microorganisms in controlled and real-field conditions. Key words - Nicosulfuron, microorganisms, dehydrogenase activity.