Optimum application time and application rate of nitrogen fertilizer in Brassica napus L.

To find proper nitrogen fertilizer application mode of rapeseed (Brassica napus L.), promote the high and stable yield of rapeseed, field experiment was carried out to study the effect of nitrogen fertilizer application modes on the yield and economic traits of Fengyou 10 rapeseed planted in two different fertility soils, and characteristics and differences of responses of different fertility soils to nitrogen fertilizer application modes were compared and analyzed. The results showed that the yield and related economic traits of rapeseed treated by nitrogen fertilizer were higher than the control group; in the nitrogen fertilizer treatment group, when the nitrogen fertilizer was applied as the base fertilizer and wintering fertilizer at the ratio of 7:3, the rapeseed yield was higher than the control group and reached the highest; when the nitrogen fertilizer was applied as the base fertilizer, wintering fertilizer, and bud fertilizer at the ratio of 5:3:2, the rapeseed yield was significantly higher than the control group but was the lowest. These indicate that sufficient nitrogen supply is the basis for normal growth and development of rape seedlings. When the pure nitrogen fertilizer was at 192 kg/ha and the ratio of base fertilizer and wintering fertilizer was 7:3, it can better coordinate the high yield of rapeseed and overall use of nitrogen fertilizer, and obtain higher rapeseed yield.