The effect of the Falcon 460 EC fungicide on soil microbial communities, enzyme activities and plant growth

Ecotoxicology, Sep 2016

Fungicides are considered to be effective crop protection chemicals in modern agriculture. However, they can also exert toxic effects on non-target organisms, including soil-dwelling microbes. Therefore, the environmental fate of fungicides has to be closely monitored. The aim of this study was to evaluate the influence of the Falcon 460 EC fungicide on microbial diversity, enzyme activity and resistance, and plant growth. Samples of sandy loam with pHKCl 7.0 were collected for laboratory analyses on experimental days 30, 60 and 90. Falcon 460 EC was applied to soil in the following doses: control (soil without the fungicide), dose recommended by the manufacturer, 30-fold higher than the recommended dose, 150-fold higher than the recommended dose and 300-fold higher than the recommended dose. The observed differences in the values of the colony development index and the eco-physiological index indicate that the mixture of spiroxamine, tebuconazole and triadimenol modified the biological diversity of the analyzed groups of soil microorganisms. Bacteria of the genus Bacillus and fungi of the genera Penicillium and Rhizopus were isolated from fungicide-contaminated soil. The tested fungicide inhibited the activity of dehydrogenases, catalase, urease, acid phosphatase and alkaline phosphatase. The greatest changes were induced by the highest fungicide dose 300-fold higher than the recommended dose. Dehydrogenases were most resistant to soil contamination. The Phytotoxkit test revealed that the analyzed fungicide inhibits seed germination capacity and root elongation. The results of this study indicate that excessive doses of the Falcon 460 EC fungicide 30-fold higher than the recommended dose to 300-fold higher than the recommended dose) can induce changes in the biological activity of soil. The analyzed microbiological and biochemical parameters are reliable indicators of the fungicide’s toxic effects on soil quality.

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The effect of the Falcon 460 EC fungicide on soil microbial communities, enzyme activities and plant growth

Ecotoxicology The effect of the Falcon 460 EC fungicide on soil microbial communities, enzyme activities and plant growth Małgorzata Baćmaga 0 1 2 ● Jadwiga Wyszkowska 0 1 2 ● Jan Kucharski 0 1 2 0 Department of Microbiology, University of Warmia and Mazury in Olsztyn , Plac Łódzki 3, Olsztyn 10-727 , Poland 1 Jan Kucharski 2 Małgorzata Baćmaga 3 Jadwiga Wyszkowska Fungicides are considered to be effective crop protection chemicals in modern agriculture. However, they can also exert toxic effects on non-target organisms, including soil-dwelling microbes. Therefore, the environmental fate of fungicides has to be closely monitored. The aim of this study was to evaluate the influence of the Falcon 460 EC fungicide on microbial diversity, enzyme activity and resistance, and plant growth. Samples of sandy loam with pHKCl 7.0 were collected for laboratory analyses on experimental days 30, 60 and 90. Falcon 460 EC was applied to soil in the following doses: control (soil without the fungicide), dose recommended by the manufacturer, 30-fold higher than the recommended dose, 150-fold higher than the recommended dose and 300-fold higher than the recommended dose. The observed differences in the values of the colony development index and the eco-physiological index indicate that the mixture of spiroxamine, tebuconazole and triadimenol modified the biological diversity of the analyzed groups of soil microorganisms. Bacteria of the genus Bacillus and fungi of the genera Penicillium and Rhizopus were isolated from fungicide-contaminated soil. The tested fungicide inhibited the activity of dehydrogenases, catalase, urease, acid phosphatase and alkaline phosphatase. The greatest changes were induced by the highest fungicide dose 300-fold higher than the Fungicides ● Soil microorganisms ● Soil enzymes ●; Soil resistance ● Phytotoxkit test - recommended dose. Dehydrogenases were most resistant to soil contamination. The Phytotoxkit test revealed that the analyzed fungicide inhibits seed germination capacity and root elongation. The results of this study indicate that excessive doses of the Falcon 460 EC fungicide 30-fold higher than the recommended dose to 300-fold higher than the recommended dose) can induce changes in the biological activity of soil. The analyzed microbiological and biochemical parameters are reliable indicators of the fungicide’s toxic effects on soil quality. Introduction The quality of life is inextricably linked with environmental health. This balance can be disturbed by biosphere contamination with fungicides which pose a serious problem for food safety and sustainable soil use. Fungicide are chemical substances that are most widely used to combat fungal diseases in production systems. They directly influence basic life processes in fungi, including respiration, sterol biosynthesis and cell division (Seiber and Kleinschmidt 2011) . Most fungal diseases in plants are difficult to treat, which is why fungicides can be applied several times during the growing season or even across several seasons. Frequent fungicide use can pose a threat to the natural environment, mainly soil, by promoting the accumulation and migration of toxic substances in ecosystems. Fungicides exert a negative effect on soil-dwelling microorganisms and biochemical processes in soil (Wyszkowska and Kucharski 2004; Banks et al. 2005; Chatterjee et al. 2013; Wightwick et al. 2013) . Their influence on the environment has to be continuously monitored to guarantee soil ecosystem homeostasis. The risks associated with fungicide use can be controlled by analyzing the biological activity of soil. Microorganisms and enzymes, which are sensitive to stress and respond to contamination faster than other parameters, are potential indicators of soil quality (Singh and Kumar 2008; Truu et al. 2008; Tejada 2009) . They participate in various soil processes, including organic matter transformation, nutrient release and decomposition of chemical compounds. Microorganisms and enzymes play a key role in the functioning of many ecosystems (Tejada et al. 2011) . The adverse effects of fungicides on soil health can be manifested by changes in the size and biodiversity of microbial populations and inhibited activity of soil enzymes (Ratcliff et al. 2006; Baćmaga et al. 2012; Zhang et al. 2014) . Fungicides can be degraded in soil by hydrolysis, evaporation, oxidation, photolysis, ionization and microbiological decomposition. Microorganisms are most effective in transforming harmful chemical substances in the soil ecosystem (Katayama et al. 2010). The rate at which fungicides are degraded is determined mainly by their chemical structure and persistence (Arias-Estéves et al. 2008) . Not all fungicides have toxic effects on soil-dwelling microorganisms. Some microbial species and strains become tolerant to chemical substances by developing defense mechanisms (Katayama et al. 2010; Komárek et al. 2010) . Fungicides can also exert tox (...truncated)


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Małgorzata Baćmaga, Jadwiga Wyszkowska, Jan Kucharski. The effect of the Falcon 460 EC fungicide on soil microbial communities, enzyme activities and plant growth, Ecotoxicology, 2016, pp. 1575-1587, Volume 25, Issue 8, DOI: 10.1007/s10646-016-1713-z