Note: It doesn't matter if you do it yourself or hire a worker for this to count. However, it must be done on a field you own, hired jobs do not count for this.This is a simple achievement it just takes time. Just grab your favorite tractor, put a fertilizing unit on the back and go to town on a field you own. The bigger the fertilizer, the faster you can get this done. It is faster to rotate through the cultivating, sowing, fertilizing and harvesting on the same field so you are working on the achievements for all 4 instead of doing one group at a time.
You can make it less a chore by buying a big field and hiring a worker then walking away while your minion does the work. You will likely have to repeat this several times depending on how much you actually played the game before starting on it.
You should also get these while completing this one.
And you should get this one naturally on the way to this one.