Abstract
Theory for coupled diffusion processes in soil is briefly described and three examples of its application to understand root-induced solubilization of nutrients given. The examples are: (1) solubilization of P through root-induced pH changes in the rhizosphere of rice plants growing in flooded soil; (2) solubilization of P through excretion of organic chelating agents from rice roots growing in aerobic soil; and (3) the effects of root geometry on P solubilization, particularly cylindrical versus planar geometry and the effect of excretion of a solubilizing agent being localized along the root axis. The theory is tested by comparing measured concentration profiles of P near roots with the predictions of the theory made using independently measured parameter values. In the examples given, the agreement between the observed and predicted concentration profiles is very good, indicating that the theory is sound and the processes involved well understood.
Similar content being viewed by others
References
Hedley M J, Kirk G J D and Santos, M B 1994 Phosphorus efficiency and the forms of soil phosphorus utilized by upland rice cultivars. Plant Soil 158, 53-62.
Kirk G J D 1999 A model of phosphate solubilization by organic anion excretion from plant roots. Eur. J. Soil Sci. 50, 369-378.
Kirk G J D and Saleque M A 1995 Solubilization of phosphate by rice plants growing in reduced soil: prediction of the amount solubilized and the resultant increase in uptake. Eur. J. Soil Sci. 46, 247-255.
Kirk G J D, Santos E E and Findenegg G R 1999a Phosphate solubilization by organic anion excretion from rice (Oryza sativa L.) growing in aerobic soil. Plant Soil 211, 11-18.
Kirk G J D, Santos E E and Santos M B 1999b Phosphate solubilization by organic anion excretion from rice growing in aerobic soil: rates of excretion and decomposition, effects on rhizosphere pH, and effects on phosphate solubility and uptake. New Phytol. 142, 185-200.
Nye P H 1983 The diffusion of two interacting solutes in soil. J. Soil Sci. 34, 677-691.
Nye P H 1984 On estimating the uptake of nutrients solubilized near roots or other surfaces. J. Soil Sci. 35, 439-446.
Saleque M A and Kirk G J D 1995 Root-induced solubilization of phosphate in the rhizosphere of lowland rice. New Phytol. 129, 325-336.
Tinker P B and Nye P H 2000 Solute movement in the rhizosphere. Oxford University Press, New York.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kirk, G.J.D. Modelling root-induced solubilization of nutrients. Plant and Soil 245, 49–57 (2002). https://doi.org/10.1023/A:1020667416624
Issue Date:
DOI: https://doi.org/10.1023/A:1020667416624