Phosphorus Fractions In Argentine Soils Of Different Pedogenesis

The distribution of phosphorus (P) in different organic and inorganic fractions was examined in five Argentinean soils of different pedogenesis. Soils were sequentially extracted to determine resin-P, bicarbonate-P, and hydroxide-P fractions. Inorganic P (IF) predominated in all soils, specially moderately resistant IP (MRIP) in Entisol, Vertisol, and Ultisol. Both MRIP and labile IP (LIP) were important in Mollisol. Organic P (OF) was at a lower concentration in all soils and moderately resistant OP (MROP) was highest in all soils, except for the Mollisol. In intermediate evolution soils, labile P (LP) was very important, Mollisol had the highest value of LP%, and the lowest was for the Ultisol, demonstrating greater dynamics of P fractions in the Mollisol, soils of high productivity in the Pampean Prairie.