Browsing by Author "Atuanya, E. I."

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    EFFECTS OF AN ORGANOCHLORINE AND PYRETHROID PESTICIDE FORMULATION ON SOIL’S CULTURABLE MICROBIAL POPULATION
    (International Journal of Technical Research & Science, 2020) Aborisade, W. T.; Atuanya, E. I.
    Non-target effect of pesticide on soil organisms is an important area of ecotoxicology, due to their roles in ecosystem sustainability. Thus, the effects of an organochlorine (endosulfan) and a synthetic pyrethroid (cypermethrin) pesticide formulation on soils’ culturable microbial population were investigated. The study was carried out on loamy sand soil sample types collected from Ondo State, Forest Reserve, Owena, Nigeria. Pesticide application rates in the range of half of the normal field rate (0.5FR), the normal field rate (FR), two times the normal field rate (2FR), four times the normal field rate (4FR) and eight times the normal field rate (8FR) were applied to the soil microcosm design in the laboratory; while the untreated soil serve as control. The experiment set up was completely randomized in three replicates and soil samples were collected from each of the set up at 5 days interval over 35 days period of exposure for analysis. The pour plate technique was used for the enumeration of bacterial and fungal colonies on nutrient agar and potato dextrose agar respectively. The results indicated that both pesticides had effects on the population of bacterial and fungal counts of the soil samples with significant (p < 0.05) adverse effect observed at the treatment rate above the normal field application rate. At lower application rates (0.5FR, FR and 2FR), temporary inhibitory effect on bacterial and fungal population were observed. The progressive increase in inhibitory effect with corresponding increase in concentration of endosulfan and cypermethrin were noticed.
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    Effects of an organophosphate (glyphosate) and a quaternary ammonium (paraquat) herbicides formulation on soils’ culturable bacterial and fungal populations
    (International Research Journal of Biological Sciences, 2022) Aborisade, W. T.; Atuanya, E. I.
    Herbicides play significant roles in weed management and contribute immensely to increase in productivity in agronomy system. However, its continuous application could have some dire effect on non-target soil microbiota. Therefore, this study assessed the impact of glyphosate and paraquat herbicides on soil culturable bacterial and fungal population. The loamy composite soil samples of forest reserve, Owena, Ondo State, Nigeria were used for the experiment. Each of the herbicide formulation was applied at the concentration rates ranged from half of the field recommended rate (0.5FR), the recommended rate (FR), two, four, and eight times the recommended rate (2, 4 and 8) FR respectively. The treatments were replicated thrice and arranged in complete randomized design, while the untreated soil samples serve as control. The standard pour plate technique was used for the enumeration of bacterial and fungal colonies after 5, 10, 15, 20, 25, 30 and 35 days of exposure. The findings showed that the glyphosate pesticides formulation applied at concentration range of 0.5 to 2FR significant stimulate bacterial populations of the soil samples while the fungal populations was not affected at the same concentration. However, the treatments at higher doses (4FR and 8FR) significantly reduced the number of bacterial and fungal counts of the soil samples. For paraquat treated soils, the treatment rate below the double recommended field rate did not have any significant effect (p > 0.05) on both bacterial and fungal populations. While the increases in inhibitory effect were observed with corresponding increases in paraquat application rates in the soil samples.