Kinetics of Phosphate Release in Tropical Soils: Adsorption, Desorption and Influence of Soil Properties

The rate at which phosphate (P) is desorbed from the soil surface into soil solution is a key factor that regulates the continuous supply of P to crops. understanding the kinetics of P desorption is paramount for effective P management in order to boost agricultural production and to minimize environmental degradation and pollution. Several kinetic models were compared for describing P desorption rates in savanna soils of varying lithogenic origins, and the effect of soil properties on P release rate was determined. Phosphate desorption rates were best described by three empirical kinetic models: Elovich equation, the parabolic diffusion equation and the fractional power equation. The rate coefficients varied widely among soils from the same parent materials and between parent materials due probably to variations in the properties of the soils. This work is intended to give an inner understanding of P behavior and management strategies especially in tropical soils with variable charge properties and high preponderance of Fe and Al oxides, most especially to researchers and graduate students that are interested in chemical kinetics and phosphorus chemistry.