Studies on the possible use of rock phosphate in Alkali soils of Egypt [electronic resource].

Includes references.

FINELY ground rock phosphate (RP) is successfully used on acidic soils where s oil acidity s lowly releases plant available P. So, the aim of this work is to assess and evaluate ;he effect of acidulation of rock phosphate and rock phosphate added to a composting materi,l1 on the availability of P in an alluvial alkali soil. Pots experiment was conducted to study the availability of acidulated rock phosphate with acetic acid (RPAA), citric acid (RPCA) and sulphuric acid (RPSA) and (RP) added with composted orange peel (RPOM) compared to triple superphosphate (TSP) for corn plants. Results show that the NaHCO3 extractable P increased in alkaline al1uvial soil treated with acidulated and (RP) added to composting of orange residues particularly (RPOM) and (RPCA). The use of (RPCA) or (RPOM) increased the availability of P and consequently increased P uptake by corn plants than the other treatments. The percentage increase of P in corn plants for TSP, RP AA, RPCA, RPSA and RPOM reached a bout 43.1 34.5,39.7,32.8 and 63.8% a bove the natural rod. phosphate (RP), respectively. The percentage increase in dry weight for TSP, RPAA, RPCA, RPSA and RPOM reached about 60.8, 35.2, 70.0,57.6 and 94.4% above the (RP), respectively It was concluded that acidulation of rock phosphate or adding the material with organic matter plays a role in the availability of P in alkaline soil beside the role of plant roots in solublying insoluble forms.

Summary in Arabic.

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