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PROF. LUÍS I. PROCHNOW

SOIL FERTILITY AND FERTILIZER SPECIALIST



- RESEARCH -
GENERAL GUIDELINES OF LATEST EXPERIMENTS
(DATA STILL NOT PUBLISHED IN SCIENTIFIC JOURNALS)

 

IMPORTANT

The information below consists in general guidelines of agronomic research dealing with the latest experiments with which I have been involved. The final papers should be soon submitted for publication in Scientific Journals. As a result of review by co-authors, invited qualified profissionals and Journal editorial comitte, information here presented can be modified when published in the Journals. In case you have a question or comment do not hesitate to contact me.


 

Title:
Agronomic Evaluation of Single Superphosphates as Influenced by Cationic Impurities for Upland and Flooded rice.

Research team:
L.I. Prochnow (coordinator), S.H. Chien, R.W. Taylor, G. Carmona, J. Henao, and E.F. Dillard.

Objective / Material and Methods:
This study was conducted to evaluate the agronomic performance of single superphosphates (SSP) containing different amounts of cationic impurities for upland and flooded rice. Three SSP products were manufactured from apatite concentrates with increasing amounts of cationic impurities, specially Fe and Al. Samples of the SSP, in the original form and water-leached, were analyzed for total amounts of Fe, Al, Si, Ca, Mg, K, Na, Ti, Ba, Sr, Zn, P, F and SO42-. The samples were scanned through an X-ray diffractometer and analyzed by XRD pattern processing for chemical species present. A greenhouse study was conducted where rates of 0, 5, 15, 30, 50 and 100 mg available P (AOAC) per kilogram of soil were applied to a Hiwassee soil (thermic Rhodic Kanhapludult). The reagent-grade monocalcium phosphate was used as a standard source of P.


 

Title:
Effect of Soil pH on the Requirement for Water-Soluble Phosphorus in Acidulated Phosphates Containing Fe-Al-P Compounds.

Research team:
L.I. Prochnow (coordinator), S.H. Chien, G. Carmona, J. Henao, E.F. Dillard, and E.R. Austin.


 

Legend: 40 mg P kg-1
0% WIF, 20% WIF, 40% WIF, 60% WIF, 80% WIF, 100% WIF.
Hiwassee Soil, pH = 6.4, Wheat, SSP RCA Araxa.

Dry-matter yield of 101 days old wheat seedlings cultivated in a Hiwassee soil (pH 6.4)
as affected by the percentage of water-insoluble P of a low-grade SSP produced from Araxá PR.


 

Objective / Material and Methods:
Use of lower-grade PR can result in higher amounts of water-insoluble fertilizer impurity compounds, thus lowering the percentage of water-soluble P in commercial phosphate fertilizers. There is some concern regarding the effect that these compounds may be having on P-fertilizer effectiveness. Legislation in some parts of the world were created in order to limit the contents of water-insoluble but citrate-soluble P in acidulated P fertilizers. Therefore, a study was conducted to determine the requirements of water-soluble P in acidulated phosphate fertilizers containing Fe-Al-P compounds. Four commercial acidulated phosphate fertilizer, varying in water-solubility and for which Fe-Al-P compounds were expected to be found in the water-insoluble fraction, were selected for the study [TSPs manufactured from Tapira and Jacupiranga apatite concentrate and SSPs manufactered from Araxa and Patos de Minas apatite concentrate]. Fertilizer impurities were collected as water-insoluble residues by washing with deionized water. Samples of the SSP, in the original form and water-leached, were analyzed for total amounts of Fe, Al, Si, Ca, Mg, K, Na, Ti, Ba, Sr, Zn, P, F and SO42-. The samples were scanned through an X-ray diffractometer and analyzed by XRD pattern processing for chemical species present. A modal analysis was applied in order to estimate the mineralogical composition of the fertilizers. Mixtures of water-soluble MCP and the water-insoluble fertilizer residues were prepared to give a wide range of water-soluble P. The fraction of water-soluble P was controlled by supplying 0, 20, 40, 60, 80 and 100% of the AOAC available P as MCP. The fertilizer mixtures were applied to supply 40 mg AOAC available P kg-1 to a thermic Rhodic kanhapludults (clay-loam) with final pH values of 5.2 ± 0.05 and 6.4 ± 0.08. A response curve was also included in the study by adding MCP alone at rates to supply 0, 20, 40, 80 and 160 mg P kg-1 soil. Wheat [Triticum aestivum (L.)] was harvested 101 days after planting.


 

Title:
Modal Analysis of the Mineralogical Composition of Single Superphosphates Produced from Araxá Phosphate Rock.

Research team:
L.I. Prochnow (coordinator), E.F. Dillard, R. Austin, S.H. Chien, C. Calvo, B. Malone.


 

X-ray diffractogram of a sample of a water-leached single superphosphate produced from a gross apatite concentrate from Araxá phosphate rock and the spectral lines for the pure compound
Fe3H9(PO4)6.6H2O - PDF file.


 

Objective / Material and Methods:
This study was conducted in order to estimate the mineralogical composition of three single superphosphates (SSP) manufactured from apatite concentrates with increasing amounts of cationic impurities, specially Fe and Al. Samples of the SSP, in the original form and water-leached, were analyzed for total amounts of Fe, Al, Si, Ca, Mg, K, Na, Ti, Ba, Sr, Zn, P, F and SO4. The samples were scanned through an X-ray diffractometer and analyzed by Jade 5.0 (XRD pattern processing) for mineral species present. A modal analysis was applied in order to estimate the mineralogical composition of each SSP. The model was based on: 1) mineral species identified by X-ray, 2) the percentages of total and water-soluble fraction of each element, 3) solubility index of the compounds and 4) chemical composition of the different compounds excluding the water of hydration.


 

Title:
Identification of Compounds Present in Single Superphosphates Produced from Brazilian Phosphate Rocks Using SEM, EDX and X-RAY Techniques.

Research team:
L.I. Prochnow (coordinator), C.A. Clemente, E.F. Dillard, A. Melfi, S. Kauwenbergh.


 

Hexagonal rod shaped crystals of (Fe, Al)3(K, Na)H8(PO4)6.6H2O identified in a sample of
single superphosphate produced from Araxá PR.


 

Objective / Material and Methods:
Scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and x-ray techniques were used to obtain data concerning the mineralogical composition of single superphosphates (SSP) produced from apatite concentrates originating from the Araxá, Jacupiranga, Catalão and Tapira igneous phosphate rock deposits. The SSP samples were investigated in the original form and after leaching with water to remove the water-soluble compounds.


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