Effects Of Nitrogen Levels And Sowing Density On Yield And Nutrition Quality Of Broadcast-sowing Rapeseed

The effects of different nitrogen levels(75, 150, 225 and 300 kg/hm~2)and different sowing density (12×10~4, 21×10~4, 30×10~4 and 39×10~4plant/hm~2) on the characteristics of leaf and pod, accumulation of dry substances, the carbon and the soluble carbohydrate and nitrogen metabolism , the yield and quality of rapeseed were studied by using rapeseed variety-Zhong you za 2. The principal results were as follows:1. These characteristics of leaf and pod were obviously affected by the amount of N applied and sowing density .Firstly, when the amount of N applied increased, leaf area, pod surface area, LAI, PAI, LAD, PAD, the chlorophyll content of pericarp and leaf increased. Secondly, with the increment of sowing density, LAI, PAI, LAD and PAD increased, but leaf area, pod surface area, the chlorophyll content of leaf decreased.2. The accumulation, distribution and transformation of dry matter were obviously affected by the amount of N applied and sowing density. The accumulation of total dry substances per plant increased with the increment of the amount of N applied and decreased with the increment of sowing density. Dry matter yields, percentage of leaf, the amount of dry matter transferred from stem and branches and its contribution to pod and grain filling rate were the highest with the nitrogen application of 300 kg/hm~2. Dry matter accumulation ,the ratio of matter outputting and translating of stem and branches ,the ratio of seed to hull were the highest in sowing density of 39×10~4plant/hm~2. The ratio of dry matter accumulation of pods and the ratio of matter translating from dry matter accumulation after polination increased at earlier stage and decreased at later stage.3. With the increment of the amount of N applied, soluble sugar content in stem and branches increased, but soluble sugar content in leaf and pod , the ratio of soluble sugar outputting and translating of stem and branches and its contribution to pod decreased. When sowing density increased, soluble sugar content of different organs decreased, while the amount of soluble sugar transferred from stem and branches and the ratio of soluble sugar translating from stem and branches increased. With the increment of the amount of N applied, crude protein in different organs and the amount of crude protein transferred from stem and branches increased. Alongside the increase of sowing density, the amount of crude protein transferred from stem and branches increased, however, the ratio of crude protein outputting of stem and branches and its contribution to pod decreased.4. With the increment of the amount of N applied and sowing density, yields extremely significant increased. Firstly, the yield was highest when the amount of N applied was 300 kg/hm~2 and sowing density was 39×10~4 plant/hm~2.Secondly, the yield was high when the...