So the way I’d want it to work would be: You have a field, the field would visually represented by various textures on the landscape that show the state of the field. The player would interact with the field using tractors and other equipment to prepare, plant and harvest the field.
Id want to be able to plug in functionality for the “states” of the field that would determine the next step the player needs to make. But also variables that can increase or decrease the harvest yield such as fertilizer, or weeds, weather, soil composition.
As for the crops themselves, they would be spawned on the field in various growth states until they reach maturity and then can be harvested.
In the grand scheme of things there would be many fields on the map the player could purchase and work, so probably a global field manager class that just logs the states and variables of the fields and informs the player.