Vol.:(0123456789) 1 3 International Journal of Environmental Science and Technology https://doi.org/10.1007/s13762-018-1862-0 ORIGINAL PAPER The microbiological response of forest soils after application of nicosulfuron, imazamox and cycloxydim V. Vasic 1  · S. Djuric 2  · T. Jafari‑Hajnal 2  · S. Orlovic 1  · S. Vasic 1  · L. Poljakovic Pajnik 1  · V. Galović 1 Received: 27 February 2017 / Revised: 13 November 2017 / Accepted: 13 June 2018 © Islamic Azad University (IAU) 2018 Abstract During application, a signifcant part of herbicide reaches the soil surface and profle which inevitably afect 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 efect of herbicides nicosulfuron, imazamoxare and cycloxydim, applied in the regeneration of oak forests on diferent 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 efect on the Azotobacter sp., while the efect of nicosulfuron was stimulative. Keywords Herbicides · Microorganisms · Soil · Oak forest Introduction The amount of applied herbicide in forestry is signifcantly less than the amount used in agriculture. Herbicide treat- ment in forestry is generally based on the experiences in intensive agricultural production (Dixon and Clay 2004). Furthermore, the agricultural experiments results are applied in forestry with more or less delay. The use of herbicides in forestry is increased in recent years in order to increase the wood production. For many forest managers, herbicide application is a popular option and more cost-efective than other available alternative measures (Vasic et al. 2014). While many herbicides are not applied directly on the soil, during application a signifcant amount reaches the soil sur- face and profle which inevitably afect the activity of micro- organisms (Lupwayi et al. 2004). There is a growing con- cern that herbicides afect the entire microbial community present in soil and that these non-target efects may alter the complex soil–microbe–plant system functioning (Seghers et al. 2003). Microorganisms play an important role in many biological processes of soil including the transformation of nitrogen, decomposition of organic matter and their release and availability. They also infuence the soil stability struc- ture and its fertility (Liu et al. 2010). Furthermore, microor- ganisms are key players in the decomposition of herbicides and other toxic substances which are introduced in the soil (Entry et al. 1994; Srivastava et al. 2014). Herbicides are not only afecting the activity of microorganisms (Ratclif et al. 2006), but their activity also depends on the herbicides resi- dues in soil. Some microorganisms are able to degrade her- bicides and use them as a source of biogenic elements and energy to maintain their physiological processes (Kizildag et al. 2014). On the other hand, herbicides may alter the number of microorganisms as well as change their activity and reproduction (Rhine et al. 2003). Herbicides that disrupt the activities of microorganisms in the soil could afect the Editorial responsibility: Zhenyao Shen. * V. Vasic vericav@uns.ac.rs 1 Institute of Lowland Forestry and Environment, University of Novi Sad, Antona Cehova 13, Novi Sad 21000, Serbia 2 Department for Environmental and Plant Protection, Faculty of Agriculture, University of Novi Sad, Trg Dositeja Obradovica 8, Novi Sad 21000, Serbia