Abstract:
Fertilizers are used in agriculture to increase crop yields, but if they are
misused, they can harm the integrity of soil ecosystems. The study's aim was to
look at the impact of inorganic fertilizers on soil microbial populations in
selected soils in the Greater Port Harcourt Area using Lethal Concentration
50 (LC50). The results revealed that the use of inorganic fertilizer altered soil
microbial characteristics in three different settings: agricultural, urban, and
industrial. For agricultural areas the maximum NPKB mean value was
0.70±0.76 ppm which was higher than the mean value of the control location
of 0.23±0.00 ppm. In the agricultural area, UREA tolerant fungi had a
lower LC50 mean value (0.43±0.09 ppm) than the control, which had a mean
value of 0.46±0.00 ppm. The mean values in the industrial and urban areas
were significantly different (p = 0.001). This study concluded that applying
UREA and NPK fertilizers to study area soils lowered the pH of soils in
agricultural sites (A1, A2, and A3). Fertilizer use in the study areas increased
the population of microorganisms at threshold concentrations but was harmful
at concentrations of 1.50 % or higher. Furthermore, findings revealed that
microorganisms were more tolerant to fertilizers in agricultural areas (higher
LC50 values) than in urban and industrial areas (lower LC50 values).
According to the findings of this study, fertilizers used in the study areas were
linked to soil microorganisms developing tolerance to NPK and UREA.
Farmers should use the recommended amounts of fertilizer to ensure the soil
ecosystem's integrity.