Abstract:
This research investigated the effect of pesticides application on the growth of two soil nitrifying bacteria
species, Nitrosomonas and Nitrobacter respectively. The bacteria were isolated from soil samples obtained from
Bingham University, Karu local government area of Nassarawa State, Nigeria. The soil bacteria were cultured
using the Manniol Yeast Extract Agar (MYEA). The bacteria isolates where identified and characterized based
on their morphology and chemical characteristics. The growth count of the bacteria after four (4) days isolation
showed increase in the bacteria growth. Nitrosomonas obtained from MYEA ranged from 23 to 102 (x105
)
cfu/g, and the growth of Nitrobacter count obtained from MYEA ranged from 24 to 97 (x105
) cfu/g. there was
an increase in bacteria growth at both control level and decrease in bacteria growth at concentration level of
20% to 100% within 120 hours of observation for Nitrosomonas species. The result shows that F_ cal 0.830 was
greater than F-tab 0.05, and Nitrobacter species. F_ cal 1.360 was greater than f-tab 0.05. Since the F- cal value
is greater than F- tab value for both the Nitrosomonas and Nitrobacter species. The Null hypothesis is rejected
and alternate is accepted. This shows that the nitrifying bacteria could not survive or grow under high pesticides
concentration. It is therefore very important to examine pesticides in order to determine it toxicity to soil
bacteria before application
