The study looked at how different amounts of potassium fertilizer affect the uptake and distribution of potassium in oil flax plants, as well as the grain yield. They found that applying 37.5kg of K2O/ha resulted in the highest grain yield. The potassium uptake in the roots, stems, and leaves increased with higher potassium levels, leading to more potassium being transported to the grains. Overall, the optimal potassium fertilizer for oil flax was 37.5kg K2O/ha.