Full explanation
Ukraine faces a real problem: short rotations, prevalence of crops returning every 2–3 years (sunflower → corn → soybean → sunflower), leading to: accumulation of crop-specific pests (sunflower broomrape, corn stalk borer), resistant weeds, soil depletion, yield decline. Science-based rotations: (1) Steppe — 5-course with fallow (fallow → winter wheat → corn → sunflower → spring barley); (2) Forest-Steppe — 7–10-course with sugar beet (winter wheat → sugar beet → spring barley → pea → winter wheat → corn → sunflower → soybean → winter wheat → spring cereals); (3) Polissia — with potato, flax, perennial grasses. Recommended minimum return intervals: sunflower 7–8 years, sugar beet 4–5 years, rapeseed 4–5 years, soybean 3–4 years, corn 2–3 years. Economics vs science: short sunflower-heavy rotation delivers higher short-term margin but depletes the farm long-term.