Effect of Phosphorus Fertilizer and Poultry Manure on P Fractions in Some Derived Savanna Soils of South Western Nigeria-A Greenhouse Study

The availability of phosphorus (P) in derived savanna soils differs among soil types and the effect of amelioration on the soil P are site specific. The study was conducted to determine the effect of P fertilization and poultry manure on the distribution of P in some derived savanna soils. The greenhouse experiment was carried out in the greenhouse of the Institute of Agricultural Research and Training (I.A.R & T), Ibadan. The treatments consisted of five rates of poultry manure (0, 5, 15 and 20 t ha-1) and five rates of phosphorus (0, 15, 30, 45 and 60 kg P ha-1) applied as single superphosphate (SSP) and this was replicated three times. The soil was cropped with maize and there were two cycles of cropping. Organic P was the largest extractable P fraction while Al-P and Ca-P fractions were the least extractable P fraction. The inorganic P fractions (Fe-P, Al-P, Ca-P, reductant soluble P and residual P) all increased in the soil series. Although there were more of increases in the P fractions in the second greenhouse studies, some treatments reduced the P fractions. Application of 30 kg P ha-1 of SSP with different rates of poultry manure was effective in increasing the total P and Fe-P fractions in Temidire series while it was the combined application of 45 kg P ha-1 of SSP with different rates of poultry manure in Apomu series.