ABSTRACT

 The effect of two commonly used herbicides force-up and Esmate, on soil microbial population was investigated. The two herbicides were applied on agricultural soil in-vitro at three rate 2.78mg1g, 5.56mglg 8.34mg/g with the middle concentration being the normal application rate. Fungi and bacteria loads (population) .were determined at four day interval for sixteen day obtained results show that the agricultural soil a sandy loam (texture) with good particle size distribution of 66.13% sand, 16.00% slit and 17. 87% clay with aid moisture content of 16.78%, adequate organic matter (2.84%) to support microbial growth and activity. The microbial flora showed their bacteria species including Pseudoinonas, Proteus, Bacillus, Escherichia, Staphylococcus and Shigella and Fungi Aspergillus, Penicillin,. Fusarcin, Cladosporuin,, Sacchronomyces and Candida. The herbicide effect manifested in the temporary inhibition of microbial population up the 8th day with bacteria load reducing from 1.93 x i0 cfu/g to 1.53 x 107cfu/g in force up and in Esmate at low concentration. The reduction was from 1.93 x l07cfulg to 1.33 x lO7cfu/g and in both cases at normal application rate while at high concentration the reduction was from 1.93 x 107cfu/g to 7.67 x lO7cfulg and 8.33 x lo7cfu/g in force up and Esmate treated soils respectively. Population recover was observed from day 12 which recorded increase in both bacteria and fungi population in the range of 1.53 to 1.83 x lo7cfu!g (fungi). It was concluded that the inhibitory effect of the herbicides were temporary as the microbes were temporary as the microbes were able to recover population increase.