J. Phys. IV France 123 (2005) 159-163
Monocalcium phosphate monohydrate concentration in soil suspension amended with organic matterF. Bennani1, M. Badraoui2 and M. Mikou1
1 Laboratoire des Matériaux et Protection de l'Environnement, Fac. des Sciences Dhar El Mehrez, Fés, Maroc
2 Departement des Sciences du Sol, I.A.V. Hassan II, Rabat, Maroc
The effect of humic substances, Fe3+, Al3+, and soil clay mineralogy on the availability of monocalcium phosphate monohydrate added at pH5 were investigated. Both solution and suspension experiments showed that humic matter chelates phosphorus and prevents the formation of less soluble forms of phosphorus than monocalcium phosphate. However, Fe3+ and Al3+ ions in the solution lead to the precipitation of Fe-P and Al-P, less soluble compounds. Organic matter, by its chelating power for Ca2+, Fe3+ and Al3+ions, explains the availability of phosphorus in solution at pH5. Clay minerals, especially smectites, induced an increase in solution phosphorus content because of their adsorption properties for Ca2+, Fe3+ and Al3+.
© EDP Sciences 2005