Effects of NPK Fertilizer on Soil Enzymes and Micro Biota

Chioma Chiemezie Okore


Soil enzymes are involved in various biochemical processes and play a vital role in maintaining soil fertility. Soil samples were collected from FederalPolytechnicNekedeSchoolfarmland in Owerri West Local Government Area of Imo State. The collected samples were further processed and analyzed using standard biochemical and microbiological procedures over a sampling period of three (3) weeks to determine the effect of NPK fertilizer on the soil micro biota and enzymes. The result revealed that microbial population of the 3rd week had the highest viable bacteria count (4.5x105) followed by the 2nd week (3.8x105) and least is the 1st week (2.4x105). Similar trend was also observed in the viable fungal count 2.2 x 105, 1.4 x 105 and 0.8 x105 in the 3rd, 2nd and 1st weeks respectively. Pseudomonas sp, Salmonella, Proteus, E.coli, Klebsiella, Staphylococcus, Aspergillus, Penicillium, Phycomycetes and Rhizopus species were isolated from the sampling area over the sampling period. The enzyme activity of the soil treated with 12.5ml, 10ml, 7.5ml and 5ml of fertilizers also revealed the effective utilization and breakdown of the chemical component of the fertilizers. This is upheld by the result obtained on the effects of the fertilizer on catalase, dehydrogenase, acid phosphatase and alkaline phosphatase enzyme activities. The statistical analysis showed that there is no significant difference in the catalase, acid and alkaline phosphatase enzyme activity, but a difference in the dehydrogenase enzyme activity at α = 0.05 degree of significance. This study therefore reveals that NPK fertilizer has great effect on the soil microbial and enzyme activity which are vital components in the maintenance of soil health and fertility.


micro biota, NPK fertilizer, soil enzymes

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