PRINCIPLES OF CROP MODEL PARAMETERIZATION

1
PRINCIPLES OF CROP MODEL PARAMETERIZATION
CROP PARAMETERS
2
1. Development rates
Determines crop duration (short long) Required
data are temperate (weather) and phenological
observations - Emergence time - Flowering
time - Physiological maturity/harvest time
Many modern HYV behave like IR72 with adapted
development rates to account for duration
3
Experimental data file
-------------------------------------------------
------------------- 8. Measured data for model
calibration and comparison
and option to force measured LAI during
simulation (instead of using
simulated values)
-----------------------------------------------
--------------------- Observed phenology
only required if program DRATES is run!! IDOYTR
16 ! Day of transplanting (give 0 if
direct-seeded) IYRTR 1992 ! Year of
transplanting (give 0 if direct-seeded) IDOYPI
58 ! Day of panicle initiation (give -99 if
not observed) IYRPI 1992 ! Year of panicle
initiation (give -99 if not observed) IDOYFL 83
! Day of flowering IYRFL 1992 ! Year of
flowering IDOYM 114 ! Day of maturity IYRM
1992 ! Year of maturity
4
2. Other crop properties

• Relative leaf growth rate
• Specific leaf area (leaf thickness)
• Assimilate partitioning factors (leaf, stem,
• panicles)
• Loss rate of leaves
• Fraction stem reserves for remobilisation

Others, depending on conditions (e.g.
cold-sensitivity, rooting depth,
5

• Required data
• Leaf area index
• Biomass of stems, green leaves, dead
• leaves, panicles
• At least 6 sampling times
• Transplanting
• Maximum tillering
• Panicle initiation (PI)
• Flowering
• Grain filling (half way flowering ? maturity)
• Maturity

6
Experimental data file
-------------------------------------------------
------------------- 8. Measured data for model
calibration and comparison
-----------------------------------------------
--------------------- Leaf Area Index (m2
leaf / m2 ground) LAI_OBS 1992., 4.,
0.00, 1992., 16., 0.03, 1992., 34.,
0.46, 1992., 58., 5.22, 1992., 68.,
5.97, 1992., 83., 5.88, 1992., 97.,
4.82, 1992., 114., 2.45 Green leaf dry wt
(kg/ha) WLVG_OBS 1992., 4., 0., 1992.,
16., 6., 1992., 34., 138., 1992., 58.,
1874., 1992., 68., 2840., 1992., 83.,
3030., 1992., 97., 2828., 1992., 114., 1432.
7
Step 1
PARAM.IN (CONTROL.DAT)
IR72 crop data file
DRATE.OUT Calibrated development rates
DRATES PROGRAM
Experiment data file with phenological
observations
Weather data file
Action 1 adapt the IR72 crop data file with new
development rates
8
Step 2
PARAM.IN (CONTROL.DAT)
Adapted IR72 crop data file with calibrated
development rates
PARAM.OUT Calibrated parameters RGRL, SLA,
FLVTB, FSTTB, FSOTB, DRLVT, FSTR
PARAM PROGRAM
Experiment data file with phenological
observations and time series of LAI, WAGT, WST,
WLVG, WLVD, WSO
Weather data file
Action 2 adapt the IR72 crop data file with new
crop parameters
9
Step 3
CONTROL.DAT
Adapted IR72 crop data file with calibrated
development rates and crop parameters
RES.DAT, OP.DAT, CHART.TXT Simulated cop growth
and development
ORYZA2000PROGRAM
Experiment data file with phenological
observations and time series of LAI, WAGT, WST,
WLVG, WLVD, WSO
Weather data file