Impact of the Herbicide Oxyfluorfen on the Activities of Some Enzymes Found in Soil and on the Populations of Soil Microorganisms

Abstract

This study assesses the effects of the herbicide oxyfluorfen on the activities of enzymes and on the populations of soil microorganisms by considering experiments on soil samples maintained in both laboratory and in field conditions. Furthermore, the molecular docking approach was used to evaluate the interactions of oxyfluorfen with enzymes found in soil. There was a dose dependent inhibitory effect of oxyfluorfen against the activities of dehydrogenase, phosphatase, protease and urease. The enzymes activities obtained for the soil samples maintained under field conditions usually reflected a different trend than those obtained under laboratory conditions, emphasizing the influence of the soil physicochemical properties. For soil samples maintained in field conditions and for the normal dose of oxyfluorfen, dehydrogenase activity recovered after 14 days and a minimum of 21 days was necessary for the recovery of phosphatase, urease and protease activity, respectively. The most important parameters of soil influencing the activities of enzymes and the populations of microorganisms were the pH, N-NO3 and N-NH4 contents. A dose dependent behavior of populations of microorganisms found in soil treated with oxyfluorfen has been shown. There was a slight grows of the colonies of microorganisms when oxyfluorfen was applied, but this growth decreased with increasing the oxyfluorfen concentration.