Nutrient Cycling in Agroecosystems

, Volume 53, Issue 3, pp 219–227 | Cite as

Phosphate adsorption and precipitation in calcareous soils: the role of calcium ions in solution and carbonate minerals

  • Simonetta Tunesi
  • Valeria Poggi
  • Carlo Gessa

Abstract

P-removal from soil solution is mainly due to adsorption and precipitation reactions. For calcareous soils two pathways have been proposed as being relevant: partitioning on soil surfaces and precipitation induced by Ca2+ ions in solution. To define P-speciation in soil and reduce P-immobilisation following fertilisation, the relative importance of these two reactions needs to be quantitatively established. This investigation, conducted on two calcareous soils, suggests that Ca-ion activity in the liquid phase is mainly responsible for the formation of insoluble Ca-P phases. Our study was carried out by determining: a) batch sorption isotherms at different slurry concentrations, times of contact, pH and indifferent electrolyte concentrations; b) supernatant isotherms on soil suspensions; c) insolubilisation kinetics of P added to soil columns. The shape of the sorption isotherms indicated that adsorption predominated at low concentrations (below approximately 0.5 mM); above this level precipitation became predominant. Precipitation from solution was demonstrated by adding increasing amounts of phosphate to soil suspension supernatants and precipitation levels comparable to those observed in sorption isotherms were obtained. Thus, carbonate mineral surfaces were not necessary for the induction of P precipitation. The formation of Ca-P mineral phases was increased with reaction time and was governed by the concentration of Ca-ions, pH and indifferent electrolyte concentration. P added at the top of soil columns was rapidly insolubilised: after 5 weeks the P-Olsen value was reduced to about 60% and P was not transported to the deepest layers but remained in the surface ones. These results suggest that, for soils with a high reservoir of exchangeable cations able to form insoluble P phases, precipitation is the predominant mechanism which reduces P availability for plants.

calcium ions carbonates P adsorption P precipitation 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Akinremi OO & Cho CM (1991a) Phosphate and accompanying cation transport in a calcareous cation-exchange resin system. Soil Sci Soc Am J 55: 959–964Google Scholar
  2. Akinremi OO & Cho CM (1991b) Phosphate transport in calcium-saturated systems: II. Experimental results in a model system. Soil Sci Soc Am J 55: 1282–1287Google Scholar
  3. Allison JD, Brown DS & Novo-gradac KJ (1991) MINTEQA2/PRODEFA2, a geochemical assessment model for environmental systems: version 3.1 USEPAGoogle Scholar
  4. Bar-Yosef B, Kafkafi U, Rosenberg R & Sposito G (1988) Phosphorous adsorption by kaolinite and montmorillonite: I. Effect of time, ionic strength, and pH. Soil Sci Soc Am J 52: 1580–1585Google Scholar
  5. Borrero C, Pena F & Torrent J (1988) Phosphate sorption by calcium carbonate in some soils of the Mediterranean part of Spain. Geoderma 42: 261–269Google Scholar
  6. Castro B. & Torrent J (1993) Phosphate availability in soils at water activities below one. Commun Soil Sci Plant Anal. 24(15&16): 2085–2092Google Scholar
  7. Chen YSR, Butler JN & Stumm W (1973) Adsorption of phosphate on alumina and kaolinite from dilute aqueous solutions. J. Colloid Interface Sci. 43: 421–436Google Scholar
  8. Cho CM (1991) Phosphate transport in calcium-saturated systems: I. Theory. Soil Sci Soc Am J 55: 1275–1281Google Scholar
  9. Griffin RA & Jurinak JJ (1973) The interaction of phosphate with calcite. Soil Sci Soc Am Proc 37: 847–850Google Scholar
  10. Harrison RB Adams F (1987) Solubility characteristics of residual phosphate in a fertilized and limed Ultisol. Soil Sci Soc Am J 51: 963–969Google Scholar
  11. Holford ICR & Mattingly GEG (1975) Phosphate sorption by Jurassic Oolitic limestones. Geoderma 13: 257–264Google Scholar
  12. Lindsay WL (1979) Chemical Equilibria in Soils. John Wiley & Sons, New YorkGoogle Scholar
  13. Matar A Torrent J & Ryan J 1992. Soil and fertilizer phosphorus and crop response in the dryland Mediterranean zone. In: Advances in Soil Sciences, vol 18, pp 81–146Google Scholar
  14. Pierzynski GM, Logan TJ, Traina SJ & Bigham JM (1990a) Phosphorus chemistry and mineralogy in excessively fertilized soils: Quantitative analysis of phosphorus-rich particles. Soil Sci Soc Am J 54: 1576–1583Google Scholar
  15. Pierzynski GM, Logan TJ, Traina SJ & Bigham JM (1990b) Phosphorus chemistry and mineralogy in excessively fertilized soils: Description of phosphorus-rich particles. Soil Sci Soc Am J 54: 1583–1589Google Scholar
  16. Pierzynski GM, Logan TJ & Traina SJ (1990c) Phosphorous chemistry in excessively fertilized soils: Solubility equilibria. Soil Sci Soc Am J 54: 1589–1595Google Scholar
  17. Salingar Y & Kochva M (1994) Solute partitioning in a calcium carbonate-phosphoric acid-water system. Soil Sci Soc Am J 58: 1628–1632Google Scholar
  18. Sharpley AN (1989) Modeling soil and plant phosphorus dynamics in calcareous and highly weathered soils. Soil Sci Soc Am J 53: 153–158Google Scholar
  19. Società Italiana di Scienza del Suolo (1985) Metodi normalizzati di analisi del suolo. Edagricole. BolognaGoogle Scholar
  20. Stumm W (1992) Chemistry of the Solid-Water Interface, pp 230. New York. Wiley & SonsGoogle Scholar
  21. Tejedor-Tejedor MI & Anderson MA (1990) Protonation of phosphate on the surface of goethite as studied by CIR-FTIR and electrophoretic mobility. Langmuir 6: 602–611Google Scholar
  22. Veith JA & Sposito G (1977) On the use of the Langmuir equation in the interpretation of ‘Adsorption’ phenomena. Soil Sci Soc Am J 41: 697–702Google Scholar

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Simonetta Tunesi
    • 1
  • Valeria Poggi
    • 1
  • Carlo Gessa
    • 1
  1. 1.U.C.I. “Scienze e Tecnologie Agroindustriali e Agroalimentari”, Istituto di Chimica AgrariaUniversità degli Studi di BolognaBolognaItaly

Personalised recommendations