In the game version where this city started, contiguous farm zone would be filled out with one farmstead with the rest of the zone being field, which would not spawn further farmsteads in the tract of land unless some field was removed.
I have to do a bit of research on this, but one tile of farmland each has one worker which remains unless taxes go too high (above about 7%). Farmsteads, which take 16 tiles (4x4), generally have fewer than 16 workers. They all have 12. This is where I need to do a bit of research. I will update this post with the number of workers per each farmstead.
Maybe there could be two zones for agriculture:
1. Farmland: As it is now.
2. Ranchland: As it was previously. Could use the same graphics, just a different zone color. Or, you could have cattle, sheep, etc roaming the land as the sailboats do the water.
I know both zoning behaviors have been used as the beta versions have progressed.
wow!