BACTERIA SOIL PROFILE AND BEHAVIOURAL GROWTH RESPONSE OF RICE PADDY TREATED WITH AGROHERBICIDES IN ABAKALIKI, EBONYI STATE, NIGERIA

Study of soil bacteria and growth behavioral response of rice paddy treated with Agro herbicides in two seasons in Abakaliki L.G.A. was investigated using standard Microbiological procedures. The results obtained from Bacteria enumeration showed that soil samples from treated rice paddy analyzed during dry season had aerobic plate count ranging from 3.2 x 109 cfu/g to 9.5 x 109 cfu/g for treated soil samples and 9.2 x 109 to 1.04 x 1010 cfu/g for the controls. The result of aerobic plate count from soil samples simulated with Butachlor and Bispyribac-sodium at varying concentrations during rainy season showed lower colony counts on 7 days of application and higher colony counts on 55 days of application. Moreover, result of aerobic plate count obtained from soil samples simulated with mixture of Butachlor and Bispyribac-sodium at varying concentrations had lowest colony count of 5 x 108 cfu/g at 3.13ml/333.3ml concentration on 7days and highest colony count of 4.1 x 109 cfu/g at same concentration on 55days after applications. The control samples showed colony counts within the ranges of 8.3 x 109 cfu/g to 8.9 x 109 cfu/g. There is no significant difference between bacteria load of treated and untreated soil samples during dry and rainy seasons at p > 0.05. The results of isolation and identification revealed that six and five bacteria were isolated from treated soil samples during dry and rainy seasons respectively. Nine bacteria were also isolated from control soil samples studied. The bacterial isolates are of the genera: Bacillus, Pseudomonus, Escherichia, Rhizobium, Azotobacter, Enterobacter, Proteus, Micrococcus, and Staphylococcus. Finally, the result of growth behavioral response of treated rice paddy showed delayed growth 15 days after application in most cases except PRE 3 that extended to 30 days while there were gradual increase in the rice growth with highest growth rates observed 55 days after application. This growth increase could be as a result of degradation of hydrocarbon component of agroherbicides used and soil enrichment by beneficial bacterial isolates initially affected by the agroherbicides. Keywords: Soil Bacteria, Growth Behavior, Rice Paddy, Agro Herbicides and Abakaliki.