Effects of N, P, K and B fertilization on quality of Brassica napus

284 field experiments were conducted in 10 main rapeseed product provinces along the Yangtze River Basin. Our research aimed at the effects of nitrogen (N), phosphorus (P), potassium (K) and boron (B) on rapeseed main quality items such as concentration of oil, protein, glucosinolate and eurcic acid in seed of double low rape (Brassica napus.with low glucosinolate and erucic acid content) and double high rape (Brassica napus.with high glucosinolate and erucic acid content). The average oil content of double low rape was 41.66%, which was 2.74% higher than double high rape. The effects of N, P, K and B fertilizer on rapeseed qualities were not uniform at different experimental sites. Oil concentration was significantly decreased, and protein concentration in the seed was increased with the increasing of N application rate. The effect of N fertilizer application on oil and protein content in double high rape was stronger than that in double low rape. Seed oil content was enhanced with the application of P, K and B fertilizer. Fertilization also influenced the glucosinolate and erucic acid content, but the effect was not significance. Oil content was positively correlated with harvest index and 1000-seed weight, negatively correlated with seed protein content. It was concluded that the combination of P, K and B fertilizer with N could alleviate oil content losses caused by unique N fertilizer application.