1. General Model Information

Name: SNAPS/SOIL - water, heat, material transport in soil


Main medium: terrestrial
Main subject: hydrology, biogeochemistry
Organization level: Ecosystems
Type of model: compartment model
Main application:
Keywords: soil water transport, heat transport, material transport, metabolites, soil water dynamics, transport of chemicals, plant uptake, unsaturated soil zone,


Herwart Behrendt
GSF-Forschungszentrum fuer Umwelt und Gesundheit
Projektgruppe fuer Umweltgefaehrdungspotentiale von Chemikalien (PUC)
P. O. Box 1129
85758 Oberschleissheim, Germany
Phone: +49-89-3187-3043
Fax : +49-89-3187-3369
email: behr@gsf.de


Herwart Behrendt


contents of the model
The model describes dynamically and simultaneously the water-, heat- and material transport in soil. The model approach for the description of the water transport is based on the model SWACRO/SWACROP resp. SWATRE. The water transport is regarded as instationary, vertically and occuring in the unsaturated soil zone. Dependent on the phenomenological stage of the plants, evaporation from soil and transpiration are calculated. At the lower boundary, free drainage is assumed. To take into consideration the influence of temperature on metabolism in soil, it is possible to determine the heat transport. Chemical transport in soil is calculated by considering diffusive/dispersive and convective processes as well as uptake by roots and degradation.
principles of the model
To calculate the updated soil water content, the model solves the one-dimensional soil water transport equation (Richards equation), a parabolic partial differential equation in second order. The soil chemical transport is based on the one dimensional convection-dispersion-equation with sink term. The model assumes equilibrium distribution between dissolved and sorbed phase, and a first-order degradation kinetic. The chemical uptake by roots is calculated as mass flow with the water uptake and is governed by the TSCF of the chemical. The TSCF (transpiration stream concentration factor) gives the concentration ratio of a chemical between the transpiration stream water and the soil solution. It correlates to the lipophilicity of the chemical.

Author of the abstract: UFIS - Environmental research information system

II. Technical Information

II.1 Executables:

Operating System(s): OS Solaris 2.4, OS Windows NT/95 Type of computer: Sun Sparc Workstation, IBM PC RAM required: 2 MB Disc space: 10 MB Portability onto other systems: PC 386 (Linux, MSDos); Convex Peripherical software required: optional: Gnuplot

II.2 Source-code:

Programming Language(s): Fortran 90

II.3 Manuals:

Manual: Behrendt, H.: 'in preperation'. Complete model documentation: Behrendt, H.; Steindl, H.; Morgenstern, M.: Methoden zur Frueherkennung und Prognose von Stoffverlagerungen in Boeden auf den Datengrundlagen des Bodeninformationssystems, GSF-Bericht, 26/94, GSF Forschungszentrum, Oberschlei\ssheim (1994). ISBN 0721-1694.

II.4 Data:

III. Mathematical Information

III.1 Mathematics

This is a list of model equations sorted by their characteristics with hypertext links for more details.

III.2 Quantities

This is a list of model quantities sorted by their characteristics with hypertext links for more details.

III.2.1 Input

III.2.2 Output

IV. References

Behrendt, H., Brueggemann, R., 1993.
Modelling the Fate of Organic Chemicals in the Soil Plant Environment: Model Study of Root Uptake of Pesticides, Chemosphere, 27, pp. 2325-2332.

Behrendt, H., Brueggemann, R., Morgenstern, M., 1995.
Numerical and Analytical Model of Pesticide Root Uptake. Model Comparison and Sensitivities., Chemosphere, 30, pp. 1905-1920.

Behrendt, H., Steindl, H., Morgenstern, M., 1994.
Methoden zur Frueherkennung und Prognose von Stoffverlagerungen in Boeden auf den Datengrundlagen des Bodeninformationssystems
GSF-Bericht 26/94, GSF Forschungszentrum, Oberschleissheim ISBN 0721-1694.

Belmans, C., Wesseling, Feddes, R.A., 1983.Simulation Model of the Water Balance of a Cropped Soil: SWATRE
J. Hydrology 63, 271-286.

Boesten, J.J.T.I., 1991.Sensivity Analysis of a Mathematical Model for Pesticide Leaching to Groundwater
Pestic. Sci. 31, 275-388.

Briggs, G.G., Bromilow, R.H., Evans, A.A., Williams, M., 1983.Relationships Between Lipophilicity and the Distribution of Non-ionised Chemicals in BarleyShoots Following Uptake by the Roots.
Pestic. Sci. 14, 492-500.

Feddes, R.A., Kowalik, P.J., Zaradny, H., 1978.Simulation of field water use and crop yield
PUDOC, Wageningen, Netherlands ISBN 90-220-0676-X.

Millington, R.J., Quirk, J.M., 1961. Permeability of Porous Soils.
Trans. Faraday Soc. 57 (1961), 1200-1207.

Monteith, J.L., 1965.Evaporation and Environment
Proc. Symp. Soc. Exp. Biol. 19, 205-234.

Penman, H.L., 1948. Natural evaporation from open water, bare, soil and grass
Proc. Roy. Soc., London, pp. 120-145.

Raes, D., van Aelst, P., Wyseure, G., 1986.ETREF, ETCROP, ETSPLIT and DEFICIT a computer package for calculating crop waterrequirements. Reference manual.
Lab. of soil a. water eng., fac. agr. sc., Leuven, Belgium.

Ragab, R., Beese, F., Ehlers, W., 1990.A Soil Water Balance and Dry Matter Production Model: I. Soil Water Balance of Oat.
Agron. J 82, 152-156.

Rijtema, P.E., 1965. An analysis of actual evapotranspirationAgri. Res. Rep. 659, PUDOC, Wageningen, NL 1965.

Ritchie, J.T., 1972. A model for predicting evaporation from a row crop with incomplete cover Water Resour. Res. 8(5), 1204-1213.

Philip, J.R., 1969.Theory of infiltration
Advan. Hydroscience 5, 216-296.

V. Further information in the World-Wide-Web

VI. Additional remarks

The model is part of the simulation model network atmosphere-plant-soil (SNAPS).

Additional information
Last review of this document by: T. Gabele: Dec 17 1997
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:49 CEST 2002

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