INTEGRATED METHODS FOR INCREASING P-SOLUBILITY OF PHOSPHATE ROCK

Document Type : Original Article

Authors

Soil Sci. Dept., Fac. Agric., Zagazig Univ., Egypt

Abstract

Laboratory experiments were carried out to study the effect of some integrated factors on solubility of phosphate rock (PR) obtained from two locations which were Abou Tartour and El-Sibaia Gharb as well as tricalcium phosphate. PRs  were crushed to pass through a 1.18-mm sieve and separated into 7 particle diameters of  500, 250, 212, 125,75 and 45 µm. Scanning Electron Microscope “SEM” and X-ray diffraction were done. P-solubility was assessed using water and 5 acids of formic (FR), Acetic (AC), tartaric (TR) oxalic (OX) and citric (CT) (each of 2%). P in Abou Tartour samples was mainly as calcium phosphate hydroxide “Ca5(PO4)6 OH. Other crystalline were silicon oxide SiO2, calcium carbonate CaCO3 and calcium di-hydrogen phosphate hydrate Ca H2PO4. P in El-Sibaia samples was mainly in form of Brushite. P contents (g kg-1) were 0.2 to 0.6 water-soluble, and 10 – 17 for Olsen extract. Ranges for the acid-extractants from the two PRs were 39-44 for CT, 25-41 for AC, 27-49 for TR, 14-28 for OX and 32-52 for FA. A tendency to increase with decreased particle size occurred. Practical aspects could be inferred regarding the use of PR for fertilization.

Keywords

Zagazig Journal of Agricultural Research
Volume 43, Issue 5
September 2016
Pages 1545-1560

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