Effects Of Nitrogen Fertilizer Application Management On Growth And Seed Yield At Different Sowing Dates For Different Maturing Rapeseed(Brassica Napus L.)

A reasonable method of nitrogen fertilizer application is beneficial to the growth and yield of rape,and can effectively utilize the fertilizer.In this study,we used rape early maturing variety Shengguang127 and medium maturing variety Huayouza62 as experimental materials.In the early and late sowing date,we set a different proportion of basal and topdressing nitrogen fertilizer,and study the effects of nitrogen fertilizer on rape growth process,individual growth,dry matter accumulation and distribution,yield and quality.The main results are as follows:1.The whole growth period of different maturing varitiesThe whole growth period of Shengguang 127 was about 4-10 d shorter than that of Shengguang 127 across two sowing dates.2.The effects of differdnt ratio of base and topdressing nitrogen fertilizer on growth process and yield of rapeseedShengguang 127 and Huayouza 62 were used to be testing materials,which are different maturing varieties.The present research set a serious of ratio of base and topdressing nitrogen fertilizer.The plant height,root neck diameter,total leaves and green leaves plant-1,and chlorophyll content were better under the ratio of 5:2:3 and 4:3:3 than under 6:1:3.The treatment of 5:2:3and 4:3:3 had a better performance in dry matter accumulation in different organs for different maturing varieties.For each sowing date,the highest dry matter weight of stem and fructification organ of Shengguang 127 and leaf organ of Huayouza 62 occurred on 5:2:3 treatment;the highest dry matter weight of leaf of Shengguang 127 and stem organ of Huayouza 62 occurred on 4:3:3 treament.The highest yield(2951 and 2748 kg/hm~2,respectively)occurred on 4:3:3 treatment in early sowing date;while it occurred on 5:2:3 treatment in late sowing date,reaching 1698 kg/hm~2 and 1320 kg/hm~2,respectively.While maintaining the amount of base fertilizer,improving the appropriate proportion of seedlings fertilizer supply increased valid branch number,laying a foundation for high yield.3.The effects of different times of topdressing nitrogen supply on growth process and yield of rapeseedGrowth rate of one time nitrogen supply(10:0:0:0)performed better compared with other treatments in earlier growth stage,while it became slower at about 110 d after sowing.The growth rate of 5:0:2:3 and 3:2:2:3 treatments performed better in during flowering to maturing stage.The maximum of each indicator occurred on 3:2:2:3 treatment in earlier sowing date,while it occurred on 5:0:2:3 treatment in late sowing date.In earlier sowing date,the maximum of dry matter weight above ground occurred on 3:2:2:3 and 5:0:2:3 treatments for these two varieties,obtained 36.27 and 34.37 g per plant,respectively.These treatments also performed well in late sowing date and the dynamic changes of dry matter accumulation of different organ were similar to that of dry matter weight above ground.Times of topdressing nitrogen supply had a significant effect on seed yield,and increasing supply times could improve yield in a certain degree.In earlier sowing date,the yield of four treatments for Shengguang 127 were 2145,2578,2889 kg/hm~2 and 2960 kg/hm~2,respectively;these treatments for Huayouza 62 were 1600,2316,2556 and 2821 kg/hm~2,respectively.The yield variance of different treatments diminished as Times of topdressing nitrogen supply increased.In late sowing date,the maximum yield occurred in tree times of topdressing nitrogen supply,reaching 1698 and 1320 kg/hm for these two varieties,respectively.Considering for yield with its components,pod number per plant and seed number per pod contributed mostly for seed yield,while one thousand weight had no effect on yield.4.The effects of slow release nitrogen and normal urea on yield of rapeseedShengguang 127 were used to be testing material,experiment in field and pot,the present research set a serious of ratio of base and topdressing of slow release and normal urea.In the field experiment,the yield of slow release fertilizer and normal urea as base fertilizer,base fertilizer with topdressing nitrogen treatment were 1764,1652 and 2591 kg/hm~2.In the pot experiment,the seed yield of above were 26.61,21.93 and 25.27 g.We can be drawn that slow release nitrogen fertilizer was better than normal urea,which can realize the purpose of saving labor.