Hydroxyapatite is an important long-term calcium and phosphorus slow release fertilizer , turning systematically soluble by the natural soil pH acidification, especially under pH 5 . On the other hand, if faster release is required an excellent alternative for sample 2h/600rpm would be the use as nanocomposites as well as verified in the work of , where the authors reported the preparation of a composite of hydroxyapatite particles dispersion in matrix of urea and starch to promote better solubilization of P and Ca.