A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH

Penn, Chad J.; Rutter, E. Bryan; Arnall, D. Brian; Camberato, James; Williams, Mark; Watkins, Patrick

doi:10.3390/agriculture8070106

Submit to this Journal Review for this Journal Edit a Special Issue

Article Menu

...

Open AccessArticle

A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH

^1,*

²,

²,

¹ and

USDA-ARS National Soil Erosion Research Laboratory, West Lafayette, IN 47907, USA

Oklahoma State University, Department of Plant and Soil Science, Stillwater, OK 74078, USA

Purdue University, Department of Agronomy, West Lafayette, IN 47907, USA

Author to whom correspondence should be addressed.

Agriculture 2018, 8(7), 106; https://doi.org/10.3390/agriculture8070106

Received: 9 May 2018 / Revised: 15 June 2018 / Accepted: 26 June 2018 / Published: 2 July 2018

(This article belongs to the Special Issue Soil Fertility)

View Full-Text Download PDF

Browse Figures

Citation Export

Abstract

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. View Full-Text

Keywords: Mehlich-3; phosphorus; soil pH; phosphorus forms; phosphorus solubility; phosphorus extractions; phosphorus testing; soil testing

▼ Show Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Share and Cite

MDPI and ACS Style

Penn, C.J.; Rutter, E.B.; Arnall, D.B.; Camberato, J.; Williams, M.; Watkins, P. A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH. Agriculture 2018, 8, 106. https://doi.org/10.3390/agriculture8070106

AMA Style

Penn CJ, Rutter EB, Arnall DB, Camberato J, Williams M, Watkins P. A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH. Agriculture. 2018; 8(7):106. https://doi.org/10.3390/agriculture8070106

Chicago/Turabian Style

Penn, Chad J., E. Bryan Rutter, D. Brian Arnall, James Camberato, Mark Williams, and Patrick Watkins. 2018. "A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH" Agriculture 8, no. 7: 106. https://doi.org/10.3390/agriculture8070106

Find Other Styles

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Metrics

Abstract views Pdf views Html views

Article Menu

A Discussion on Mehlich-3 Phosphorus Extraction from the Perspective of Governing Chemical Reactions and Phases: Impact of Soil pH

Abstract

Share and Cite

Article Metrics

Article Access Statistics

Article Access Map by Country/Region

Further Information

Guidelines

MDPI Initiatives

Follow MDPI