Optimum cropping pattern is as follows :
| Crop | cropping pattern (ha) |
| Soft wheat | 0 |
| Durum wheat | 73.333 |
| sugar beet | 0 |
| Rapeseed | 18.333 |
| Potato | 18.333 |
| Barley | 0 |
The income is as follows : 173 100€.
The solution model is : modelEco_rotation1.gms
The choice of the model can be explained by the cropping pattern constraints and gross margins of crops (the water constraint is not binding). Observe the gross margins of each crop ( display) : command). It can be noted that the crop with the highest gross margin is potato. The land area dedicated to potato is limited by the rotation constraint, and the model represent a 1/6 of the total land area dedicated to potato crops. The second crop in terms of gross margin is durum wheat ; the model produces durum wheat until it reaches the rotation constraint limit (2 years out of 3). Every year the farmer divides his land area as follows : 4/6 for durum wheat, 1/6 for potato and 1/6 for rapeseed.
Rotation is therefore as follows : durum wheat, durum wheat, rapeseed, durum wheat, durum wheat, potato. The choice of crop selected by the model allows him to follow this rotation while maintaining the same areas dedicated to the different crops every year. He will have to follow the cropping pattern, that is to say rotate crops on the different farm plots.
For example :
