Effect of [N-(Phosphonomethl)-glycine] (Glyphosate) Herbicide on Soil Microbial Population

Abstract

Aims: To determine the effect of [N-(phosphonomethl)-glycine] (glyphosate) herbicide on soil bacterial and fungal population. Study Design:The effect glyphosate herbicide on soil microorganisms population on 2 different farm land was determined by Isolation of bacteria and fungi from untreated and Glyphosate herbicide treated soils using Nutrient agar and Potatoes dextrose agar (PDA) for the bacteria and fungi respectively. The number of bacteria and fungi present in both treated and untreated soil was then enumerated and the isolates determined. Place and Duration of Study: The study is a cross sectional research and was conducted on two Farm lands located at Yola capital city of Adamawa state Nigeria wheresoil samples were collected and Microbiology laboratory of Modibbo Adama University Yola were the sample was processed and analyzed. The study was conducted from February to May of 2021. Methodology: Bacteria and fungi were isolated from soil samples before and after treatment of the soils with N-(phosphonomethl)-glycine(Glyphosate) herbicide at different concentration, the bacteria and fungi populations isolated both before and after the treatment were compared. Results: The study showed that Glyphosate herbicide caused reduction in the bacterial and fungal count from 3 days of treatment up to 15 days. The bacterial count reduced from 6.1x108cfu/g in the untreated soil to 1.6x108cfu/g on the treatment. Also the fungal count reduced from 1.0x108cfu/g in the untreated soil to 5.0x107cfu/g after 15days of soil treatment. Both the bacterial and fungal count continues to show a gradual decrease up to 15 days in the treated soil. However, several bacteria and fungi were isolated with Bacillus spp. and Micrococcus spp. having the bacteria with highest occurrence with 42(19.91%) and Aspergillusspp. as the fungi with the highest occurrence with 12(42.85%). Statistical analysis of the data obtained indicated that At 95% confidence level, there is a significant difference in the population of bacteria and fungi before and after the soil treatment P-value(T˃t)=.001 Conclusion: The study revealed that Glyphosate herbicide has a negative effect on soil bacteria and fungi population.