Readsorption of phosphate by soil during acid and alkaline extractions

Rodriguez, D. and Mendoza, R. (1993) Readsorption of phosphate by soil during acid and alkaline extractions. Communications in Soil Science and Plant Analysis, 24 1-2: 133-147. doi:10.1080/00103629309368786

Author Rodriguez, D.
Mendoza, R.
Title Readsorption of phosphate by soil during acid and alkaline extractions
Journal name Communications in Soil Science and Plant Analysis   Check publisher's open access policy
ISSN 0010-3624
Publication date 1993
Sub-type Article (original research)
DOI 10.1080/00103629309368786
Volume 24
Issue 1-2
Start page 133
End page 147
Total pages 15
Place of publication Philadelphia, PA, United States
Publisher Taylor & Francis
Language eng
Formatted abstract
The results of phosphate (P) extraction (Pe) from soil as a function of shaking time (t) are presented. Three different extractant solutions and four soils from the Argentinean wheat belt were used. Shaking times were up to 80 hours with soil samples of one gram each. The solutions used were: 20 mL 0.5M sodium bicarbonate at pH 8.5; 7 mL 0.025M hydrochloric acid plus 0.03M ammonium fluoride; and 10 mL 0.01M calcium chloride. The effect of shaking time on Pe is explained in terms of competition effects. A model is presented which assumes that phosphate is first displaced from the soil, then partially readsorbed from the solution. Thus, the net effect on the amount of P present in the extracting solution at a given time, depends on the algebraic sum of the two separate terms involved. In general, Pe increases with shaking time for the sodium bicarbonate, decreases for the ammonium fluoride, and changes only slightly for the calcium chloride solution. Both terms, the amount of P initially displaced and the amount of P readsorbed, increased with shaking time. For each soil, the net effect on Pe is the result of both the shaking time and the other particular conditions of the extractant method. The results show that the rate of change in Pe is high enough to warrant an accurate shaking time control if the usual methods are used (Bray 1, 1–5 min; and Olsen, 30 min).
Keyword Mechanistic model
Extractant solutions
Shaking time
Extractant method
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Queensland Alliance for Agriculture and Food Innovation
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Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
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Created: Mon, 07 Mar 2011, 15:23:24 EST