Relationship of Soil Phosphorus Pools with Bray 1 Phosphorus in Some Acid Soils of Central Southern Cameroon

We measured phosphorus (P) chemical pools of genetic horizons of five representative pedons from central southern Cameroon. Our objectives were to assess the relative abundance of P pools and to empirically model their interrelations and contributions to a P availability index. The fractionation scheme followed a modified Hedley sequential procedure with anion exchange resin, 0.5 M sodium bicarbonate (NaHCO3; Pi and Po), 0.1 M sodium hydroxide (NaOH; Pi and Po), 0.5 M hydrochloric acid (HCl; Pi), and 2 M sulfuric acid (H2SO4) after soil ignition at 550 oC. Resin P, sodium bicarbonate (NaHCO3-P; Pi and Po), and HCl-Pi-extractable pools accounted for 1.0, 5.7 and 0.7 % of total P (TP) respectively. The NaOH-P and residual P pools measured through 2 M H2SO4 emerged as the largest and most variable pools, accounting for 86.2% of TP. The relative abundance of extracted P pools decreased in the order resin P NaHCO3-P HCl-P NaOH-P H2SO4-P. Bray 1 P was significantly correlated with all P pools except NaHCO3-Pi, NaOH-Pi, and residual pools.