Different zones of farming can have priority.
For example, say your town had too much food but not enough silkweed for your weaver. You could tick a box named “Priority” on the farm zone which is growing silkweed and the farmers will make sure there is crop growing in there before planting or harvesting any other plots.
sorta of related
i’d like to be able to ‘domesticate’ plants so that farmers or workers will automatically harvest bushes or cacti
I did have this idea too, it can be annoying when you have a lot of berry bushes and having to constantly harvest them, it would look nice if every so often the farmers harvested them inamongst their crops.