EFFECT OF PHOSPHORUS FERTILIZER ON SOME SOIL CHEMICAL PROPERTIES AND NITROGEN FIXATION OF LEGUMES AT BAUCHI

Research was conducted during the 2004, 2005 and 2006 cropping seasons to study the effect of phosphorus fertilizer on some soil chemical properties and nitrogen fixation of legumes at Bauchi. Composite soil samples were collected from sites before planting and after harvesting at the depths of 0-15 and 15-30cm. The treatment consisted of legumes namely; cowpea local variety (Yar Sokoto), groundnuts (Ex-Dakar) and soybean (TGX1448-2E) and four levels of phosphorus fertilizer (0, 13.2, 26.4 and 39.6kgP/ha). The experiment was laid out in a randomized complete block design (RCBD) with three replications. The result shows that soil pH., organic carbon, total nitrogen and available phosphorus increased in the soil samples collected after harvesting as compared to the soils sample before planting across the depths. Phosphorus fertilizer application significantly (P=0.05) increase nitrogen fixation up to 26.4kgP/ha, but decline significantly (P=0.05) at higher levels of 39.6kgP/ha in the cropping seasons. Legumes differ significantly (P=0.05) in their ability to fixed nitrogen, with soybean fixing the highest amount of nitrogen in the cropping seasons. Interaction between phosphorus fertilizer application and legumes show that in 2004 cropping seasons the application of 13.2kgP/ha gave significantly (P=0.05) the same amount of nitrogen fixed irrespective of the legumes, but in 2005 and 2006 cropping seasons, the interaction shows that at 0kgP/ha phosphorus levels of the amount of nitrogen fixed by the legumes was significantly the same. It is concluded that the application of phosphorus fertilizer did not only increase the nutrient status of the soil but enhance the nitrogen fixation ability of the legumes for a sustainable legume production and soil fertility management at Bauch