Length : around 15 minutes
Run the techn1.gms model (which you wrote in activity 11A , or download it from the Model Library) and save it under the name technique2.gms. Add the crop water needs (model problem statement found below). Add the new irrigation constraint and display the results of the optimum areas for each crop in the form of a table (row : crops ; columns : technologies ; and one “total” column.)
| Reminder : In order to display a table, a two-dimensional parameter must be created (with the character * replacing the domain when the parameter is not set to a specific domain), values must be attributed, and it can then be created using the display command. For example, in a “one row / one column” table, the following rows show the optimum total income value. Copy (warning : do not copy-paste !) the rows and observe the result in the .lst file :Parameter RESULT(*,*); RESULT(‘REVENU’,’TOTAL’) = Z.L; Display RESULT ; |
« A given farm can grow three types of crop, wheat, maize and tomato, and use two different crop practices, extensive and intensive. The area to be cultivated and technology to be used must be determined, knowing that :
The objective of the farmer is to maximize his income.
The needs are :
| Water needs (thousands of m3/ha) | Labour needs (h/ha) | |||
| Technology | extensive | intensive | extensive | Intensive |
| Wheat | 0 | 2 | 15 | 25 |
| Maize | 4 | 6 | 45 | 50 |
| Tomato | 3 | 5 | 80 | 100 |
Yields and costs are as follows :
| Yield (ton/ha) | Cost (€/ha) | |||
| Technology | extensive | intensive | extensive | Intensive |
| Wheat | 4.5 | 5.0 | 250 | 300 |
| Maize | 8.0 | 10.0 | 400 | 500 |
| Tomato | 13.0 | 16.0 | 1200 | 1350 |
The selling price of wheat is 150€/ton, that of maize is 150€/ton, and that of tomato 185€/ton.
The farm area is 50 ha, and the farmer can work 2000 hours a year and has 150 thousand m3 for irrigation. »
What cropping pattern is chosen and what is the optimum income for the farmer ?
Then check the solution
