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Sudan Journal of Agricultural Research

Assessment of the chemical reactivity and agronomical potential of various phosphate rocks
 

Gadelkarim M. Madibbo


Abstract:
 

The chemical composition of five different phosphate rocks (PR) was evaluated. The apatite of the various rock sources showed a wide variation in the elemental composition. The highest F (4.1 %) and CaO (52.2%) and the lowest R₂O₃J contents (0.67%) were attained with Morocco PR. Brazil PR (Araxa) showed the highest total P₂O₅ (37%), but the lowest F(2.9%) and SiO₂ (0.74%) contents. Isomorphous substitution (CO₃^-2 and F^- for PO₄^-3) was shown to be a major factor affecting the reactivity of the PR. Sources of PRs were also evaluated using a Redding soil (pH 5.9) cropped to alfalfa. Both results of the laboratory and the greenhouse, rank the PRs as follows: Morocco> Central Florida> Peru> Tennessee> Brazil.

 

Keywords:

Sudan Journal of Agricultural Research Vol. 1(1998) PP. 13-16