Effects of cultural practices on yield and quality of rape cultivar Suyou 4 with double low content in rapeseed

A field experiment with the rape cultivar Suyou 4 was carried out under different planting densities,fertilizer application rates and fertilizer distribution ratios.The results showed that the suitable cultural practices to gain a high rapeseed yield were 7 500 plants667 m2 planting density,22 kg667 m2 nitrogen fertilizer application rate and 4∶2∶4 fertilizer distribution ratio(basal fertilizer∶fertilizer applied in late December∶fertilizer applied in bolting),and the yield could reach 207.33 kg667 m2.The fertilizer application rate was a major factor affecting the yield,and the planting density and fertilizer distribution ratio were the next.The effective pods per unit area increased with the density and rate increasing and were influenced by the ratio under a low planting density.The 1000-seed weight increased with the rate increasing and the density decreasing but changed less with the ratio varying.The rate had a positive effect on the seeds per pod.The key to the high-yield culture of Suyou 4 was the effective pods per unit area.The oil and protein contents in rapeseed decreased with increasing the rate but increased with increasing the basal fertilizer and the fertilizer applied in late December and decreasing the fertilizer applied in bolting.