1. General Model Information

Name: ORYZA_0

Acronym: ORYZA_0

Main medium: terrestrial
Main subject: agriculture, biogeochemistry
Organization level: population
Type of model: compartment model
Main application:
Keywords: crop growth, rice, biomass accumulation, limited nitrogen (N) uptake, daily total global radiation


Dr.ir. H.F.M. ten Berge.
Research Institute for Agrobiology and Soil Fertility (AB-DLO), Dept. Agrosystems Research, P.O.Box 14, 6700 AA Wageningen, THE NETHERLANDS.
Phone: +31.317.475951 / 475953
Fax: +31.317.423110
email: sarpwag@ab.dlo.nl / h.f.m.tenberge@ab.dlo.nl



The model ORYZA_0 simulates biomass accumulation in rice as limited by nitrogen (N) uptake and daily total global radiation. It is based on a very limited set of relations expressing soil and crop processes. The equations used in describing both the soil and the crop component of the model are stripped down to the bare basics. ORYZA_0 can, therefore, be regarded as a real summary model of N limited rice growth. The complexity found in the more detailed crop growth and development models, such as ORYZA1* and ORYZA_N*, is avoided here; explicit formulations of phenological development, leaf area development, light interception, assimilation, respiration, conversion of glucose into dry matter, partitioning of dry matter, remobilization of carbohydrates, and the formation of sink size are all omitted. The net results of all these processes are expressed in a few coefficients. Contrary to the other ORYZA models, however, ORYZA_0 includes a soil component to describe, albeit in empirical form, N uptake. Attention is also given to crop N demand as a factor that might limit N uptake. The model can also be used with leaf N as observed forcing function and then omits all uptake and allocation processes. Most of the parameters used in the model can be easily obtained from field studies. A user-friendly interface (MANAGE-N*) exists to optimize N application schemes based on ORYZA_0.

Purpose of the model:

Model parentage: None.

Source of the Abstract CAMASE Register of Agro-ecosystems Models

II. Technical Information

II.1 Executables:

Operating System(s): Costs: : Dfl. 350,=. Comments:

II.2 Source-code:

Programming Language(s): Microsoft FORTRAN, FSE*, and FST*.

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

Rate variables: Crop growth, N allocation to leaves, N uptake, N application, N translocation, soil N supply.

State variables: Amount of N in the leaf canopy, total N uptake, total biomass, total N applied.

III.2.1 Input

Fraction of N allocated to the leaves, N fraction in panicles, maximum leaf nitrogen pool, global radiation use efficiency, leaf N use efficiency, soil N supply, recovery of applied fertilizer-N, date of planting, date of flowering, harvest date. Input check in model: No.

III.2.2 Output

Biomass accumulation.
Basic spatial unit: m2 and ha.
Time interval of simulation: Day.

IV. References

Berge, H.F.M. ten, M.C.S. Wopereis, J.J.M. Riethoven, T.M. Thiyagarajan & R. Sivasamy, 1994. The ORYZA_0 model applied to optimize nitrogen use in rice. In: Proceedings of the 'International Workshop on Nitrogen Management and Modelling in Irrigated Rice', held at the Crop Experiment Station, Rural Development Administration, Suweon, Korea, 1-10 November 1993. DLO-CABO, Wageningen. WAU-TPE, Wageningen. IRRI, Los Banos. 235-253
Drenth, H., H.F.M. ten Berge & J.J.M. Riethoven (Eds.), 1994. ORYZA simulation modules for potential and nitrogen limited rice production. SARP Research Proceedings. AB-DLO/Wageningen, WAU-TPE/Wageningen, IRRI/Los Banos. 223 pp.
Thiyagarajan, T.M., H.F.M. ten Berge & M.C.S. Wopereis (Ed.), May 1995. Nitrogen management studies in irrigated rice: proceedings of the SARP Applications Workshop held at the International Rice Research Institute (IRRI), Los Banos, Philippines, 18 April - 6 May, 1994. Wageningen, DLO-Research Institute for Agrobiology and Soil Fertility. Wageningen, WAU-Department of Theoretical Production Ecology. Los Banos, International Rice Research Institute. SARP Research Proceedings. 109 pp.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: Tue Sep 23 1997
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:46 CEST 2002

Go back to Register of Ecological Models (R E M)