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Greenhouse Evaluation of Phosphorus Sources Produced from a Low‐Reactive Brazilian Phosphate Rock
Author(s) -
Prochnow L. I.,
Chien S. H.,
Carmona G.,
Henao J.
Publication year - 2004
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2004.0761
Subject(s) - lolium perenne , dry matter , phosphorite , phosphorus , chemistry , agronomy , solubility , phosphate , greenhouse , zoology , poaceae , biology , organic chemistry
The Patos de Minas phosphate rock (PR) in Brazil is not suitable for direct application due to its low reactivity or for commercial production of P fertilizers because of its high Fe‐Al content. The objective of this study was to investigate the potential agronomic effectiveness of P sources with low water solubility produced from the PR. The P treatments were (i) compacted granular Patos PR with a single superphosphate (SSP) containing high water‐soluble P content at a P ratio of 50:50, (ii) powdered low‐grade single superphosphate (LG SSP) produced from Patos PR with low water solubility, (iii) powdered Patos PR, (iv) powdered mixture of PR and SSP at 50:50 P ratio, and (v) compacted granular SSP. The P sources were incorporated into an acid soil with pH 5.3 at 0, 10, 25, 50, and 100 mg P kg −1 to grow wheat ( Triticum aestivum L.) and ryegrass ( Lolium perenne L.) as test crops in a greenhouse study. We confirmed that Patos PR was low in agronomic effectiveness, only 1 and 30% as effective as SSP in producing dry matter yield of wheat and ryegrass, respectively. There were no significant differences between LG SSP or compacted PR+SSP [PR+SSP(C)] and SSP in dry matter yields of both crops, whereas mixed PR+SSP was less effective than PR+SSP(C) compared with granular SSP. Compacted PR+SSP and LG SSP can be potential P sources to be produced from the low‐grade PR that could not be used either for direct application or acidulated P fertilizers.