1. General Model Information

Name: LOwland Water BALance - Water balance for puddled lowland (rice) soils

Acronym: LOWBAL1

Main medium: terrestrial
Main subject: biogeochemistry
Organization level: ecosystem
Type of model: compartment model
Main application:
Keywords: soil, puddled lowland soil, water balance, rice, irrigation, rainfed, Et, drainage, capacity cascade model, soil cracking and shrinkage, bypass flow


Dr.ir. B.A.M. Bouman
Research Institute for Agrobiology and Soil Fertility (AB-DLO)
Dept. Agrosystems Research
P.O.Box 14
6700 AA Wageningen
Tel. +31.8370.75972
Fax +31.8370.23110
Email: bouman@ab.agro.nl

Dr.ir. B.A.M. Bouman


Dr.ir. B.A.M. Bouman


LOWBAL (LOwland Water BALance) is a simple water balance model for puddled lowland soil under rice production. The model keeps track of the amount of water in the puddled layer by book-keeping of the inputs (rainfall, irrigation) and outputs (evaporation, transpiration, seepage and percolation). The model can handle irrigated and rainfed conditions. In the irrigated situation, irrigation is treated as a dynamically simulated variable: a fixed amount of irrigation water is applied whenever the simulated depth of ponded water drops below a - user-defined - minimum level. When the soil dries out (rainfed situation), the puddled layer shrinks linearly with (decreasing) water content. Cracks can develop that penetrate the compacted layer in the bottom of the puddled layer at a certain minimum water content value. Water losses by seepage and percolation are then determined by the drainage rate of the subsoil below the puddled layer. Both shrinkage and cracking are irreversible. Roots of the rice crop are considered to be confined to the puddled layer only and no water extraction of the subsoil is simulated.

Author of the abstract:
CAMASE Register of Agro-ecosystems Models

II. Technical Information

II.1 Executables:

Operating System(s): VAX computer, IBM compatible PC/AT >= 640 Kb RAM Availability: Executable and Source code are available from the Author A user contract is mandatory, in principle this software product may be used only fornon-commercial purposes. The product is accompanied by an AB-DLO/TPE-WAU Licenceagreement and warranty disclaimer. Costs: Dfl. 270,=.

II.2 Source-code:

Programming Language(s): FORTRAN-77 (in FSE) ( see section II.1 )

II.3 Manuals:

Bouman, B.A.M., 1993. ORYZA_W, Rice growth model for irrigated and water-limitedconditions. SARP report, March 1993. AB-DLO. 67 pp.

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Bouman, B.A.M., 1993.
Rice growth model for irrigated and water-limited conditions.
SARP report, March 1993. AB-DLO. 67 pp.

Bouman, B.A.M., M.C.S. Wopereis, M.J. Kropff, H.F.M. ten Berge & T.P.Tuong, 1994.
Understanding the water use efficiency of flooded rice fields. IISimulation and sensitivity analysis.
In press by Agricultural Water Management.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: T. Gabele: 30. 07. 1997 -
Status of the document:
last modified by Joachim Benz Mon Jul 2 18:31:37 CEST 2007

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