Thesis Abstract

The effect of pesticides, chchlorodipheny trichloroethane (DDY) and Benzene hexaxhoride (BHc) on the microflora of the three types of soil (loamy, clay and sandy soil) was conducted. The serial dietitian technique was employed up to 10-3 using nutrient agar, potato dextrose agar and sabour and agar plates. The isolation of both bacterial and fungal organisms were made before treating the soil types with the two pesticides), D.D.T and BHC. and after treating the soil types with D.D.T after treating and BHc.

The highest bacterial count before treating the soil types with D.D.T and BHc was got in loamy soil with 133 per ml having PH 7.1, followed by clay soil with 78 per ml and least was sandy soil with 42 per ml. while the highest bacterial count after treating the soil types with D.D.T was gotten in loamy soil 105 per ml, followed by clay soil with 51 and least count was got in sandy with 28 per ml. Also the highest bacterial count after treatment with BHc was obtained in loamy soil with 12F per ml, followed by clay soil with 64 per ml and the least count was got from sand soil with 37 per ml.

The highest bacterial isolate from all the soil types before treatment with the two pesticides was pseudomonas with 25 per ml, followed by Bacillus SPP with 24 per ml, and next was achnomycetes with 19 per ml while the least bacterial organism was Rhizobrium SPP. The fungal organisms isolates were Aspergillus species, syncophatastrum species, pernicillum species and mucor species. The results of this project showed that there was reduction in microflora of the soil types after treatment separately with the two pesticides. But the effect was more with D.D.T than with BHc. Also the effects of the two pesticides was highest in sandy soil followed by clay and lastly the loamy soil.

Thesis Overview