ORYZA2000 v2.00 (May 2003) - Water balance

Instead of only PADDY, now three water balance models are available: PADDY, SAWAH and SAHEL. Whereas PADDY is only suitable for typical poorly-drained lowland rice soils, SAWAH can be used for both lowland rice soils and regular ‘upland’ soils, and SAHEL for well-drained upland soils. SAWAH, and especially SAHEL, were included to simulate upland and ‘aerobic’ rice (see below). 

The choice of the water balance model to be used is defined in the experimental data file: 

*-- WATBAL is Choice of water balance

*   needs only be given when PRODENV = 'WATER BALANCE'

WATBAL = 'PADDY'   ! PADDY water balance (for lowland soils)

*WATBAL = 'SAHEL'   ! SAHEL water balance (for freely draining upland soils)

*WATBAL = 'SAWAH'   ! SAWAH water balance (for lowland or upland soils)

Each water balance model requires its own data input in the soil data file. The name of the soil data file is specified in the file CONTROL.DAT. To check whether the correct data file is supplied for a selected water balance model in the experimental data file, an identification label, SCODE, should be provided in the top of each soil data file: 

SCODE = ‘SAHEL’    in a data file meant for the model SAHEL water balance;

SCODE = ‘SAWAH’  in a data file meant for the model SAWAH water balance;

SCODE = ‘PADDY’   in a data file meant for the model PADDY water balance.

In each of the three water balance models, the variable SCODE is declared ‘character’: 

CHARACTER (5) SCODE 

In the initialization section of the water balance models, the value of SCODE is read from the soil data file, and it is checked whether the value matches the water balance model. For example in the model SAHEL: 

!----- Read code to recognize the correctness of supplied soil file

CALL RDSCHA('SCODE',SCODE)

IF (SCODE .NE. 'SAHEL') THEN

CALL FATALERR ('SAHEL','Wrong soil input file for SAHEL water balance')

END IF 

The model PADDY is extensively described in Chapter 6 of the book ORYZA2000: modeling lowland rice. Below, summary descriptions and example input data files are given for SAHEL and SAWAH. 

Click HERE to read more about SAHEL model.

Click HERE to read more about SAWAH model.