Effects of application amounts of nitrogen, phosphate and potassium and planting density on yield and quality of rapeseed

The effects of application amounts of nitrogen, phosphate and potassium and planting density on yield and quality of rape cultivar, Huayouza 9, under the fixed N: P2O5: K2O ratio (1: 0.55: 0.8) conditions of different nitrogen levels (135, 225 and 315 kg/ha) and planting densities (15104, 45104 and 75104 plant/ha). The results show that yields of rapeseed are increased with the increases of fertilizer and density, and the influences of fertilizer levels on the increased yield rates are more effective than those of the densities. The increases of densities under the low fertilizer level have significant effect on the increased yields. There are great differences on main economic characters and yield when the fertilizer level and density are changed. However, the density has more influence on the number of the effective branches and pods. When the increased density by 30104 plant/ha, the number of effective branches is reduced 1.73.8 per plant. The oil content of rapeseed of main stem is higher than that of branches, while the contents of protein and glucosinolate are lower in the main stems. There would be a fall in the content of oil and an increase of protein and glucosinolate in rapeseed when the amount of fertilizer is raised, while when the density is increased, there would be an increase in oil content and falls in the contents of protein and glucosinolate of main stem and branches, and a fall in the glucosinolate content of the whole plant. Considering reducing fertilizer application, saving cost and increase efficiency, the optimum levels of N, P2O5 and K2O application for Huayouza 9 are 135225 kg/ha, 75124 kg/ha and 108180 kg/ha respectively, and density is increased appropriately in the range of 4510475104 plant/ha in order to obtain seed yield more than 3000kg/ha.