The best predecessors for corn are crops that do not suppress its growth through allelopathic effects and that leave enough productive moisture in the soil.
They also help reduce weed pressure, avoid shared pests and diseases, and improve overall field conditions for the next season.
In the forest steppe, good predecessors include winter wheat, legumes, buckwheat and potatoes. With adequate moisture, sugar beet can also be acceptable before spring sowing.
In Polissia, crop choice depends on soil fertility; legumes, potatoes, sugar beet, winter cereals, flax and lupin are considered optimal. Expanding corn in rotations here can increase grain output without sharply reducing other crops.
In the steppe zone, the highest productivity is achieved after winter cereals on black or occupied fallow and after legumes. Early cereals and corn are acceptable, while Sudan grass and sunflower are undesirable predecessors.
Worse predecessors are crops that deplete moisture and nutrients, spread corn pests and diseases, or leave toxic residues that inhibit root development.
