For this achievement you will need to own 10 fields and 10 tractors with some type of equipment. See "Seigneur" for the method to buy fields. You will likely acquire 3-5 tractors while working on the "Contracter" achievement. Rent or purchase the remaining tractors and plows, the cheapest for both is fine, need to have 10. Drive each tractor to a different field. Once you have a tractor in each field, use the hire a worker for that field. Switch to each tractor using or and hire a worker for each. The tractor will disappear when you have hired a worker for it. You can perform a specific type of job on a field even if the field does not require it. For jobs that require you to fill the equipment, like spraying or watering, you must have the equipment full before you can hire a worker to use it.