The study looked at how potassium fertilizer affects the growth of rapeseed plants in Eastern Hubei. By testing different amounts of potassium, researchers found that applying 180 kg/hm2 of potassium led to the highest seed yield and plant growth. This optimal amount also resulted in the highest net profit for farmers. Based on their findings, the recommended potassium fertilization rate for rapeseed in the area is 160 kg/hm2.