Response of nitrifying bacteria in concretionary soil of Northern Ghana to phosphorus fertilization

Abstract

Large quantities of P fertilizer are applied to savanna soils of northern Ghana to increase crop yield. Little is known about the influence of this fertilizer on the activity of nitrifying bacteria in these soils. This study was conducted to ascertain the possibility of using the population of nitrifying bacteria as an index of the effect of applied P on nitrifiers in the soils. The most probable number method was employed to enumerate nitrifying bacteria in soils from two experimental corn fields fertilized at rates of 30, 60, and 90 kg P ha-1 in northern Ghana. Nitrite oxidizing bacteria were not significantly stimulated by P application. There was however, a distinct and large increase in total population of nitrifying bacteria with increasing P application. Correlation between total P content of the soils and population of nitrifying bacteria was significant (p≤0.05), indicating that P application influenced the growth of nitrifying bacteria in these soils.