Plant and Soil

, Volume 74, Issue 1, pp 93–100 | Cite as

Sensitivity of simulated phosphorus uptake to parameters used by a mechanistic-mathematical model

  • M. Silberbush
  • S. A. Barber


Chemical methods for determination of soil P available to plants do not take into account the effect of roots on P uptake by the plant. Moreover, the relative significance of root parameters, as compared to soil supply parameters in determining P uptake, is unknown. Simulation models have been verified for P uptake by corn (Zea mays L.) and soybeans (Glycine max L. Merr.). The objective of this paper was to use the Cushman simulation model, which has 11 plant and soil parameters, for a sensitivity analysis of the parameters involved in P uptake. Initial parameter values were those obtained from soybeans grown in Raub (Aquic Argiudoll) silt loam. Phosphorus uptake was simulated with each parameter changed independently, from 0.5 to 2.0 times initial value while all the other parameters remained constant. In addition, P uptake was simulated where interrelated parameters were changed according to their dependence. Root growth rate and root radius were the most sensitive parameters influencing P uptake. Soil P supply parameters were more sensitive than root physiological uptake parameters. Phosphorus concentration in soil solution affected P uptake more than the diffusion coefficient and buffer power. Reduction of root radius while root volume was maintained constant by increasing root length increased P uptake. Where both soil volume and root volume were kept constant, reduction of root radius to the size of root hairs or mycorrhizal hyphae gave the greatest P uptake.

Key words

Diffusion coefficient Plant phosphorus nutrition Root length Root radius Soil solution P 


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  1. 1.
    Claassen N and Barber S A 1976 Simulation model for nutrient uptake from soil by a growing plant root system. Agron. J. 68, 961–964.Google Scholar
  2. 2.
    Cooper K M and Tinker P B 1978 Translocation and transfer of nutrients in vesticular-arbuscular mycorrhizas. II. Uptake and translocation of phosphorus, zinc and sulphur. New Phytol. 81, 43–52.Google Scholar
  3. 3.
    Cushman J H 1979 An analytical solution to solute transport near root surfaces for low initial concentration. I. Equations development. Soil Sci. Soc. Am. J. 43, 1087–1090.Google Scholar
  4. 4.
    Fox R L and Kamprath E J 1970 Phosphate sorption isotherms for evaluating the phosphate requirements of soils. Soil Sci. Soc. Am. Proc. 34, 902–907.Google Scholar
  5. 5.
    Nye P H 1968 The use of exchange isotherms to determine diffusion coefficients in soil. Int. Congr. Soil Sci. Trans. 9th (Adelaide, Australia) I, 117–126.Google Scholar
  6. 6.
    Olsen S R and Kasawneh F E 1980 Use and limitations of physical-chemical criteria for assessing the status of phosphorus in soils. p. 361–410.In The Role of Phosphorus in Agriculture. Eds. F E Khasawneh, E C Sample, and E J Kamprath. Am. Soc. of Agron., Madison, WI.Google Scholar
  7. 7.
    Schenk M K and Barber S A 1979 Phosphate uptake by corn as affected by soil characteristics and root morphology. Soil Sci. Soc. Am. J. 43, 880–883.Google Scholar
  8. 8.
    Silberbush M and Barber S A 1983 Prediction of phosphorus and potassium uptake by soybeans with a mechanistic mathematical model. Soil Sci. Soc. Am. J. 47, 262–265.Google Scholar
  9. 9.
    Silberbush M and Barber S A 1983 Sensitivity analysis of parameters used in simulating potassium uptake with a mechanistic mathematical model. Agron. J. (In press).Google Scholar
  10. 10.
    Warncke D D and Barber S A 1972 Diffusion of zinc in soil. II. The influence of soil bulk density and its interaction with soil moisture. Soil Sci. Soc. Am. Proc. 36, 42–46.Google Scholar

Copyright information

© Martinus Nijhoff/Dr W. Junk Publishers 1983

Authors and Affiliations

  • M. Silberbush
    • 1
  • S. A. Barber
    • 1
  1. 1.Agronomy DepartmentPurdue UniversityWest LafayetteUSA

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