Length : around 30 minutes
i. Loosening the labour constraint 
Answer the questions using the solutions of the labour1.gms model (written in activity 12A or downloadable from the Model Library).
The farmer now has the possibility of hiring workers at 10€ per hour. Modify the labour1.gms model (which you can call travail2.gms)
« A given farm can grow three types of crop, wheat, maize and tomato, and use two crop practices, extensive and intensive. The area to be cultivated must be determined for each production-technology combination, knowing that :
The objective of the farmer is maximize his income.
Water needs are as follows :
| Water needs (thousands of m3) | ||
| Technology | extensive | intensive |
| Wheat | 0 | 2 |
| Maize | 4 | 6 |
| Tomato | 3 | 5 |
Labour needs are as follows .
| Labour needs (h/ha) | |||
| Technology | Period | ||
| Winter | Summer | ||
| Wheat | extensive | 10 | 5 |
| intensive | 15 | 10 | |
| Maize | extensive | 10 | 35 |
| Intensive | 10 | 40 | |
| Tomato | extensive | 10 | 70 |
| Intensive | 10 | 90 | |
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 150€/ton, and that of tomato 185€/ton.
The farm area is 50 ha, and the farmer can work 1000 hours in summer and 1000 hours in winter, and has 150 thousand m3 for irrigation. »
Answer the following questions :
- What are the effects observed on constraints and variables ?
- The new cropping pattern approach is different, why ?
Then check the solution : 
ii. Displaying results 
Add a row for the number of paid working hours in winter and summer to the RESULT table in activity 12A.
Then check the solution :
