EFFECT OF NITROGEN FERTILIZER (UREA) ON SOIL ACIDITY INDICES UNDERLOWLAND RICE CULTIVATION IN YOLA, NIGERIA

The experiment was conducted for two years to determine the effect of N fertilizer application rates (0, 50, 100 and 150 kg/ha on grain yield, pH, calcium (Ca), magnesium (Mg), base and acidity saturation of the soil in FARO 44 lowland rice cultivation. Grain yield was significantly (P= 0.05) affected by the N fertilizer rates; it increased linearly with N rates. The grain yield increased was by 41.59, 66.21 and 79.87% for 50, 100 and 150 kg ha-1 N rates respectively as compared to control. pH, Ca, Mg and base saturations decreased with increased in N rates compared to the control. Acidity saturation increased with increasing N rates. The acidity saturation increased was by 3.57, 4.92 and 6.68% for 50, 100 and 150 kg ha-1 N rates respectively as compared to control. In order to sustain the soil, regular monitoring and adoption of management practices such as split application of fertilizers, incorporation of organic matter and soil conservation measures to control erosion and leaching of base cations that minimizes soil acidification processes should be imbibed in lowland rice cultivation in Adamawa state, Nigeria.