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Crop Yield Forecasting

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2.2.8. The <strong>Crop</strong> Growth Simulation Model<br />

WOFOST is a semi-deterministic process-based model of physiological processes that<br />

simulates crop growth at a daily time interval. A simplified scheme of the WOFOST model’s<br />

input and output variables is shown in Figure 1.4. The following input variables (a complete<br />

list of which is available in Table B1.1., Annex B1.3) are used:<br />

• 46 crop parameters, including 34 single parameters and 12 multiple parameter<br />

tables (dynamic parameters that are a function of the DVS or of temperature);<br />

• Variety (regional cultivars, some parameters of which are modified);<br />

• <strong>Crop</strong> calendar;<br />

• Start of season (emergence or sowing); and<br />

• End of season (maturity or harvest).<br />

The simulation runs from sowing to maturity and is based on the crop’s response to weather<br />

and soil moisture conditions. The following variables are calculated:<br />

• Phenology (sowing-flowering-maturity);<br />

• Light interception;<br />

• Assimilation (Photosynthesis);<br />

• Respiration;<br />

• Assimilate partitioning;<br />

• Leaf area dynamics (growth and decay):<br />

• Evapotranspiration; and<br />

• Soil/water balance.<br />

38<br />

<strong>Crop</strong> <strong>Yield</strong> <strong>Forecasting</strong>: Methodological and Institutional Aspects

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