The microbiological response of forest soils after application of nicosulfuron, imazamox and cycloxydim

During application, a significant part of herbicide reaches the soil surface and profile which inevitably affect the activity of microorganisms. Some microorganisms are able to degrade herbicides and use them as a source of biogenic elements and energy to maintain their physiological processes. On the other hand, herbicides may alter the number of microorganisms as well as change their activity and reproduction. For that reason, it is of most importance to determine the correlation between microorganisms and herbicides in the soil. The aim of this study was to examine the effect of herbicides nicosulfuron, imazamoxare and cycloxydim, applied in the regeneration of oak forests on different groups of microorganisms in the soil. Microbiological research included the determination of the total number of bacteria, fungi, actinomycetes, azotobacter and aminoheterotrophs. The number of microorganisms was determined by introducing a diluted soil suspension into the proper media and counted per 1 g of absolutely dry soil. The investigated herbicides cycloxydim, nicosulfuron and imazamoxare reduced the total number of bacteria and aminoheterothrops but increased the number of actinomycetes and fungi in forest soils. Imazamox and cycloxydim had a negative effect on the Azotobacter sp., while the effect of nicosulfuron was stimulative.