Soil Microbial Inhibitions on the Impact of Four Herbicides on Plantain Plantation (Musa paradisiaca) in FECOLART, Owerri- West, Imo State, Nigeria
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Abstract
The increased use of herbicides in agricultural soils causes contamination of the soil with toxic chemicals. These chemicals exert certain effects on non-target organisms, including soil microorganisms which are responsible for the numerous biological processes essential for increase in soil fertility and food production. In line with this, the study assesses the Soil Microbial inhibitions of Four Herbicides using concentration level of 0.33mg/l diluted with 10 litres of water and applied on 1 hectare of land: Glyphosinate; Basta -15; Roundup and Atrazine were applied on Plantain Plantation (Musa paradisiaca) in FECOLART. Soil samples were collected at 0-15cm and 15 – 30 cm depths with the herbicides evaluation: 1DAT, 2DAT, 3DAT, 4DAT 10DAT respectively. The results showed that , the herbicides treatments significantly inhibited the development of microbial populations in the soil and the degree of inhibitions closely related to the rates of their applications which varied with the type of herbicide used. Glyphosinate caused the highest percentage of inhibitory effect on bacterial populations at 15-30cm with a scanty growth of Streptococcus progenies when applied at the recommended field rate, but at 0-15cm, yielded a moderate growth of Clostridium when isolated, and when sporadically applied Basta-15 yielded no bacterial growth in the soil. The results also shown that, the fungal populations were mostly affected by Roundup at 3DAT.Atrazine recorded the least inhibitory effect on soil microbial population. The highest fungal inhibition was observed at 3 days after treatment (DAT) followed by a drastic decrease of inhibition by 4 DAT, while 10 DAT recorded zero inhibition. Ultimately, the result showed that inhibition of fungi and bacterial growth increased with increased herbicide rates. The degree of fungal growth inhibition by the herbicides were in order of Glyphosinate >3DAT, Roundup >3DAT, Basta >2DAT and Atrazine> 1DAT. The degree of growth inhibition by the herbicides on bacteria were in order of Basta >1DAT; Glyphosinate > 2DAT; Roundup >3DAT, and Atrazine>2DAT
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References
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