Effect of chemical fertilizer on the bacteria population and its characterization in paddy soil / Nurul E’zzati Zaid, Nur Maizatul Idayu Othman and Aida Soraya Shamsuddin

An experiment had been conducted to determine the effect of chemical fertilizer on the population of microorganisms and characterization of the microorganisms in fertilized and non-fertilized paddy soil. The experiment was designed by using two treatments with three replications. Two treatments consisted of chemical fertilizer treatment (with fertilizer) and the other one as control (zero fertilizer). Rice seeds were cultivated in pots. The soil samples were taken every week for serial dilution to indicate the population of bacteria in the soil. Colony Formic Unit (CFU) result of fertilized soil and non-fertilized soil indicated there is no significant differences in bacterial population (test at a= 0.1). The characteristics of bacteria were determined by using microscopic observation. Pure culture was streak on the microscopic slide glass for Gram Staining to identify whether it is positive or negative. For the result, at the end of the treatment, nonfertilized soil recorded the shape of bacilli (57%), cocci (18%), staphylococci (4%) and diplo-cocci (4%). In fertilized soil recorded in bacilli (33%), cocci at (24%), streptobacilli (4%) and streptococci (4%). Meanwhile, in non-fertilized soil, the color of bacteria recorded is milky white (39%), white (29%), brown (4%), yellow (11%) and yellowish white (18%). Fertilized soil recorded in milky white (33%), white (29%), brown (4%), yellow (0%) and yellowish white (33%) in the end of the treatment. For Gram positive, it showed higher percentage (50%) compared to Gram negative bacteria (42.86%) in non-fertilized soils. While, in fertilized soil, the result showed 42.86 % in Gram positive compared to 57.14% in Gram negative. The chemical fertilizer application have no effect on microbial population. The reason might be the duration of fertilizer application. The period is too short for the microbial reaction towards the chemical fertilizer in the soil.