Planting the same crop over and over is fine in Rimworld but in real life this causes issues.
The soil looses its fertility and pests and diseases happily make themselves a permanent home as their preferred food source is guaranteed.
Crop rotation helps return nutrients to the soil without synthetic inputs.
This mod lowers the yield of crops when the same crop is planted in the same spot multiple times.
The yield gets lower and lower each time, but rotating the crop instead increases the yield.
This only affects plants in growing-zones that are destroyed upon harvesting.
You can also select multiple crops for growing-zones and pawns will change crop after each harvest.
The change happens per cell, so unless you are using a mod like Growth Sync your fields may soon look a bit random as plants may grow at different speeds.
Pawns will also look at skill requirements when switching crop and skip any crop that no colonist can plant.
The gizmo for extra crops are only visible if the base-crop selected is a harvestable crop that is not a tree and where the plant is destroyed when harvesting. The selectable extra plants are also limited by this.
So zones for trees, flowers and crops that do not need replanting after harvest will not have any extra plants selectable.
You can also switch to seasonal rotation where you can select a different crop to be sown for each season.
This option will only be visible in maps that do not have permanent winter/summer.
Growing zones will also have an extra action for burning the crops to increase the yield. This is locked behind the basic crop-rotation research. A pawn will then come over to the field, set it on fire and stand watch to stop the fire from spreading.
Mod-options
Mod requires:
Harmony