A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH
Mehlich-3 (M3) is one of the most common agronomic and environmental phosphorus (P) extractants for determining P fertilizer requirements and the potential for non-point source pollution. Understanding how soil properties impact M3 extractability can improve our ability to properly use this soil tes...
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MDPI AG
2018-07-01
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| Series: | Agriculture |
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| Online Access: | http://www.mdpi.com/2077-0472/8/7/106 |
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| author | Chad J. Penn E. Bryan Rutter D. Brian Arnall James Camberato Mark Williams Patrick Watkins |
| author_facet | Chad J. Penn E. Bryan Rutter D. Brian Arnall James Camberato Mark Williams Patrick Watkins |
| author_sort | Chad J. Penn |
| collection | DOAJ |
| description | Mehlich-3 (M3) is one of the most common agronomic and environmental phosphorus (P) extractants for determining P fertilizer requirements and the potential for non-point source pollution. Understanding how soil properties impact M3 extractability can improve our ability to properly use this soil test. The objectives of this study were to investigate the impact of soil pH on P extractability by M3 and water in different soils containing equal total P, and to ascertain information about mechanisms of M3-P extraction. Soil pH at four field sites was previously adjusted to a range of approximately 4.5–7.5. Soils (Grant, Dale, Teller, Easpur) were characterized, and P was extracted with M3 and water. Extraction of Mehlich-3 P decreased 40% to 55% with increasing pH, which was potentially due to changing P forms, partial neutralization of extractant pH, and consumption of extractant fluoride (F−) by non P-containing calcium (Ca) minerals. Water-soluble P (WSP) increased with increasing pH up to pH 6–7. Mehlich-3 P and WSP were not positively correlated except for one soil type. Mehlich-3 P is best utilized with WSP as indicators of quantity and intensity, respectively. Use of M3-P alone at pH < 5.5 may overestimate solubility. Further research should examine the suitability of M3-P at pH > 7. |
| first_indexed | 2024-12-16T17:56:58Z |
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| id | doaj.art-3585dd69f9284a7ea47516cb1c83bcb1 |
| institution | Directory Open Access Journal |
| issn | 2077-0472 |
| language | English |
| last_indexed | 2024-12-16T17:56:58Z |
| publishDate | 2018-07-01 |
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| record_format | Article |
| series | Agriculture |
| spelling | doaj.art-3585dd69f9284a7ea47516cb1c83bcb12022-12-21T22:22:08ZengMDPI AGAgriculture2077-04722018-07-018710610.3390/agriculture8070106agriculture8070106A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pHChad J. Penn0E. Bryan Rutter1D. Brian Arnall2James Camberato3Mark Williams4Patrick Watkins5USDA-ARS National Soil Erosion Research Laboratory, West Lafayette, IN 47907, USAOklahoma State University, Department of Plant and Soil Science, Stillwater, OK 74078, USAOklahoma State University, Department of Plant and Soil Science, Stillwater, OK 74078, USAPurdue University, Department of Agronomy, West Lafayette, IN 47907, USAUSDA-ARS National Soil Erosion Research Laboratory, West Lafayette, IN 47907, USAOklahoma State University, Department of Plant and Soil Science, Stillwater, OK 74078, USAMehlich-3 (M3) is one of the most common agronomic and environmental phosphorus (P) extractants for determining P fertilizer requirements and the potential for non-point source pollution. Understanding how soil properties impact M3 extractability can improve our ability to properly use this soil test. The objectives of this study were to investigate the impact of soil pH on P extractability by M3 and water in different soils containing equal total P, and to ascertain information about mechanisms of M3-P extraction. Soil pH at four field sites was previously adjusted to a range of approximately 4.5–7.5. Soils (Grant, Dale, Teller, Easpur) were characterized, and P was extracted with M3 and water. Extraction of Mehlich-3 P decreased 40% to 55% with increasing pH, which was potentially due to changing P forms, partial neutralization of extractant pH, and consumption of extractant fluoride (F−) by non P-containing calcium (Ca) minerals. Water-soluble P (WSP) increased with increasing pH up to pH 6–7. Mehlich-3 P and WSP were not positively correlated except for one soil type. Mehlich-3 P is best utilized with WSP as indicators of quantity and intensity, respectively. Use of M3-P alone at pH < 5.5 may overestimate solubility. Further research should examine the suitability of M3-P at pH > 7.http://www.mdpi.com/2077-0472/8/7/106Mehlich-3phosphorussoil pHphosphorus formsphosphorus solubilityphosphorus extractionsphosphorus testingsoil testing |
| spellingShingle | Chad J. Penn E. Bryan Rutter D. Brian Arnall James Camberato Mark Williams Patrick Watkins A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH Agriculture Mehlich-3 phosphorus soil pH phosphorus forms phosphorus solubility phosphorus extractions phosphorus testing soil testing |
| title | A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH |
| title_full | A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH |
| title_fullStr | A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH |
| title_full_unstemmed | A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH |
| title_short | A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH |
| title_sort | discussion on mehlich 3 phosphorus extraction from the perspective of governing chemical reactions and phases impact of soil ph |
| topic | Mehlich-3 phosphorus soil pH phosphorus forms phosphorus solubility phosphorus extractions phosphorus testing soil testing |
| url | http://www.mdpi.com/2077-0472/8/7/106 |
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