Abstract
A field study was conducted to investigate the distribution of phosphorus forms in coastal plain sands of Akwa Ibom State. Five representative soil profiles were dug, one each at Uyo, Etinan, Abak, Ikot Ekpene and Eket. Soil samples were taken from six soil horizons per profile at a depth of 0-20, 20- 40, 40-60, 60-80, 80-100 and 100-130 cm. Results revealed that, total phosphorus (P) varied widely from 650.00 to 1237.050 mg/kg. Organic P also varied from 23.00 to 332.50 mg/kg with values decreasing with depth in Uyo, Etinan, Abak, Ikot Ekpene and Eket. The relative abundance of the active P fractions was in the order of Al –P> Ca –P >Fe- P > Sal –P in all the soils. Occluded P was relatively low in the soils with values ranges from 2.61 to 7.48 mg/kg, reductant soluble P ranges from 2.61-7.22. Occluded Fe –P and Al-P ranges from 17.40 to 45.24 and 43.50 – 121.80 mg/kg respectively. Available P estimates indicates that the soils are rich in P with values above the critical levels in all the soils. The relationship between the various active forms of soil P indicates that saloid – P correlated with sand (r =0.505 **), Al-P correlated with k (r=0.495**) Fe – P correlated with k (r=0.543**) and negatively with sand (r=-0.369*) Ca-P correlated with mg (r= 0.363*), Occl-Fe and Al- P correlated negatively with sand (r=-0.432*) and silt (r=0.428) Routine soil analysis before P fertilizer recommendation and adequate applications of organic manure are management imperatives for these soils.