EFFECT OF PESTICIDE (CHLORYPYRIPHOS) ON THE GROWTH OF NITRIFYING BACTERIA (Nitrosomonas AND Nitrobacter species) ISOLATED FROM THE SOIL

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.