1. General Model Information

Name: The model with two parameters for microbial degradation of pesticides


Main medium: terrestrial
Main subject: biogeochemistry
Organization level: ecosystem
Type of model: ordinary differential equations
Main application:
Keywords: pesticide,degradation,simple model


Fax :



The concentration of pesticide at time t, is related to the growth of pesticide-degrading microorganisms, at the initial concentration of pesticide, and the concentration of pesticide when -dx/dt reaches its maximum, if the time when -dx/dt reaches its maximum, and t1/2 the half-time for the loss of pesticide.

Model purpose
Describing the variation with time of the concentration of organic compounds (e.g. pesticides) in soil.

Source of the Abstract:
Joergensen S.E., B. Halling-Soerensen and S.N Nielsen (Edts.) 1996: Handbook of Environmental and Ecological Modelling. CRC Press Boca Raton et al. 672 pp.

II. Technical Information

II.1 Executables:

Operating System(s): DOS

II.2 Source-code:

Programming Language(s): BASIC

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Liu, D.S., and Zhang, S.M., 1987. Kinetic model for degradative processes of pesticides in soil. Ecol. Modelling, 37: 131-138.
Liu, D.S.; Zhang, S.M. and Li, Z.G. 1988. Study on rate model of microbial degradation of pesticides in soil. Ecol. Modelling, 41: 75- 84. ( Model with 3 parameters for microbial degradation of pesticides)
Zhang, S.M.; Liu, D.S.; Wang, Z.S. and Ma, X.F. 1993. A kinetic model describing the effect of temperature on the loss rate pesticides in soil. Ecol. Modelling, 70: 115- 125.

V. Further information in the World-Wide-Web

VI. Additional remarks

The rate of degradation is proportional to the concentration of pesticide (x) and the number of pesticide-degrading microorganisms (m) i.e., -dx/dt=kxm, where k is the rate constant. This concept is the basic premise from which the model with two parameters is derived.
Last review of this document by: R. Patzak , 03.September 1997
Status of the document:
last modified by Joachim Benz Tue May 9 14:01:33 CEST 2006

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