this probably will be endgame content.
the general idea is to make planting easier when you have a lot of fields, like in the fourth farm. a lot of space, and you need to plant every crop by yourself? that's harsh. so here are some possbilities to make it easier:

1. planting vehicle. a new kind of car, where you can assign 1-6 (ideally 1-9) seed stacks. then you drive and whenever the car collides with a plot that's eligable, it'll put a plant down.
2. planting planner. an app either on your phone or your drone where you can assign crops to plots. when you harvest it, assuming the crop doesn't re-grow, the same seed will be auto-planted again either right away or on the next day, taking the seeds either from your inventory or from your storage
3. planting by drone. compatibly with #2, you can then have various UI-tools like of selecting areas where to plant the crop, planting so to say.

i hope one of those possibilities is to your liking, if not ideas and implementations that improve the planting in the late-game are welcome :)