Soil Microbial Activity in Maize Crop after Application of Nicosulfuron
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.