The study looked at how different amounts of nitrogen fertilizer affected the yield and quality of a type of rapeseed called 'Suyou 4'. They found that the best amount of nitrogen fertilizer for this type of rapeseed was between 270 and 313 kg per hectare. Increasing the nitrogen fertilizer led to higher rapeseed yield by increasing the number of effective pods. The primary branches of the rapeseed were not affected much by the nitrogen fertilizer, but the secondary branches were. As the nitrogen fertilizer amount increased, the oil and protein contents of the rapeseed increased and then decreased, but the erucic acid and glucosinolate contents were not directly affected.