WOFOST Application
WOFOST (World Food Studies Crop Growth Model) is a special computer model used to evaluate yields of different crops. Weather conditions, soil data and crop characteristics are taken into consideration during yields simulation. WOFOST model can simulate potential, attainable (limited) and reduced yields. In order to see the difference between potential and limited yields and to distinguish impact of irrigation (or other factors) on crop production, simulation of a certain crop type was conducted.
It was decided to simulate growth of potato 702. This crop is mainly grown in southern region of France. In order to get reliable and accurate results, the area under the investigation had to be limited. Consequently, Corsica Island as one of the southern French areas was selected for the WOFOST simulation. Another necessary data that entered the simulation was information on soil. Due to the fact that Corsica is mountainous island, the texture of soil was defined as coarse and, consequently, coarse type of soil was indicated for crop growth modeling. In addition, to perform simulation, weather conditions had to be provided. Due to this, meteorological data from one of four available climatic stations was used. Regarding the time scale, period of 10 years (from 1990 till 1999) was selected. Date of emergence was the start date for the simulation and full ripe date was the date when the stimulation stopped. No information about the nutrition level was provided.
Crop growth simulation was run to attain potential and water-limited yield results. As potato is a tuberous crop, dry weight of living storage organs (WSO) represented obtained yields. When values of storage organs received from potential and water-limited growth simulation were compared, an insignificant gap between these two yields was noted. It could be seen from Table 1 that the average potential yield derived from WOFOST crop growth model is about 16,4 t/ha while the average attainable yield is 16,2 t/ha. The average difference between these two indicators is only 0,2 t/ha which proves to be insignificant. The difference between potential and water-limited yield reveals that in a case of insufficient irrigation or reduced amount of precipitations, southern region of France (Corsica) will experience marginal decrease in potato 702 yields.
In spite of the results that were obtained and benefits of the WOFOST model for agricultural practice, there are several limitations regarding application usage. First limitation relates to the size of an area under investigation. WOFOST application uses certain sets of data. The bigger the area under investigation is, the wider difference is in soil, weather and crop properties. Due to this, it is advisable to apply WOFOST model only to relatively small areas where scaling errors will be minor. Another limitation of the WOFOST application is that in reality crop production relies on a number of additional factors which are not taken into consideration during the simulation. For instance, the influence of socio-economic factors or technologies on southern part of France was neglected. Moreover, management is assumed to be performed professionally which is …