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Agronomy Journal Abstract -

Sensitivity Analysis of Parameters Used in Simulating K Uptake with a Mechanistic Mathematical Model1


This article in AJ

  1. Vol. 75 No. 6, p. 851-854
    Received: July 22, 1982

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  1. M. Silberbush and
  2. S. A. Barber2



In recent years, mechanistic mathematical models for predicting nutrient uptake by plants growing in soil have been developed and verified for P and K uptake. However, detailed sensitivity analyses from an agronomic viewpoint have not been published. The objective of this paper is to determine the relative significance of each of the 11 parameters in the Cushman (1979) model for predicting K uptake by ‘Williams 79’ soybeans (Glycine mar L.) from Raub (fine-silty, mixed, mesic Aquic Argiudoli) silt loam using a sensitivity analysis. Each variable was used at 0.5 to 2.0 times the initial level obtained experimentally while the remaining parameters were held constant. Analyses were also made where interdependent parameters were varied simultaneously by using assumed interdependance between specified variables. Predicted K uptake was influenced more by changes in root length and root radius than by similar changes in any other parameter. Changes in the soil supply parameters; initial concentration in soil solution, soil buffer power, and effective diffusion coefficient influenced K uptake more than changes in the plant kinetic parameters for the soil-plant system used.

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