Now, our farms will be able to be upgraded. In fact, it is only the plant quality that will be improved. Depending on current latitude, your will upgrade your farm with your agronomist. For now, the maximum level is 7. Each resource has its ideal latitude. More we go away from this latitude less we will able to improve our resources. As this plot isn't in the ideal latitude for the wheat, the level maximum for this farm is 5 instead of 7. If you knew in reality, the ideal latitude to sow (tobacco, sugar, cotton, coffee, ...), we would be really interested for all those information.