The study looked at how different levels of potassium fertilizer affect the growth and yield of oil flax plants. They tested four levels of potassium fertilizer on oil flax plants in a field experiment. The results showed that plants treated with medium potassium had the highest dry matter accumulation and grain yield. Leaves and stalks were the main parts of the plant where dry matter accumulated. The plants transported a significant amount of dry matter to the seeds. Overall, the plants treated with medium potassium had the best efficiency in using potassium fertilizer for growth and yield.