Plowing - Click in one corner, and instead of letting go of the click, drag creating a box like the old land claiming box. Release the click to designate the entire boxed area to be plowed. Character goes square by square plowing the box automatically. The land remains designated for plowing until the plowing is done, or it is specifically canceled. If the plower stops plowing, the designation remains there, and can be picked up again after drinking tea or whatever stopped the plower. Multiple farmers can plow the same designation. The same thing can be done with seeds when right clicking a plowed lot.
After a crop is harvested (the last time for multiple harvest crops like grapes) the land becomes fallow and needs to be plowed again before re-use. The second plowing should take much less time as you just need to turn the soil, and you're not working at digging through grass or tree roots or anything.