Effect Of Nitrogen Fertilizer Management On Yield And Quality Of Direct-sowing Rapeseed(Brassica Napus L.)

In order to find out an appropriate nitrogen fertilizer management way of high density direct-seeding rapeseed, ChuannongyouNo.3and ZhongshuangNo.11were used to study the effects of agronomic traits, dry matter accumulation, nitrogen absorption and utilization, yield and quality of direct-sowing rapeseed under different fertilizer application(0,6,12,18,24kgN/667m2) and application times of nitrogen fertilizer (all as base fertilizer before sowing, application as two times before sowing and seedling, application as three times before sowing, seedling and bolting stage,). The results are as follows:1. The plant height, height of first branch increased with the increase of N fertilizer application. Properly N fertilizer application can promote the collar diameter and the number of primary branches of rapeseed, but when more than180kg/ha pure nitrogen and270kg/ha pure nitrogen respectively showed inhibitory effect. N fertilizer application as one time was conducive to the increase of collar diameter and number of primary branches of rapeseed. N fertilizer application as two times can significantly increased first branch height. N fertilizer application as three times can improved plant height and the length of main inflorescence of the ZhongshuangNo.11.2. The dry matter accumulation increased with N fertilizer application increased at the seedling, flowering and harvesting. There was had a significant difference in N12, N18, N24and NO, but no significant difference between N12, N18, N24. In the process of rapeseed growth, N fertilizer split application was conducive to the dry matter accumulation, but at the maturity of plant, the final dry matter accumulation of ZhongshuangNo.11had maximum value when N fertilizer in full as basal application, and ChuannongyouNo.3had maximum value when N fertilizer applying three times treatment. At seedling, leaves proportion of the total dry matter accumulation take the maximum when use pure nitrogen180kg/ha. At flowering, leaves proportion was increased with the increase of N fertilizer application. At harvesting, the dry matter of stem accounted for about half of total dry matter accumulation, oilseed and shell had similar proportion. Compare with flowering, the dry matter proportion of stem decreased at harvesting.3. The N accumulation of stem, oil, shell and plant were increased with N fertilizer application increased, besides, there were had significant differences between ZhongshuangNo.11and ChuannongyouNo.3at the N accumulation of stem, oil, shell. For ZhongshuangNo.11, the shell and total N accumulation was decreased when N fertilizer split application. For ChuannongyouNo.3, the stem N accumulation was decreased and the shell N accumulation was increased when N fertilizer split application. The PEN, AEN and PFPN of ZhongshuangNo.11and Chuannongyou-No.3were decreased with N fertilizer application increased. There had’nt significant difference between the indexes of nitrogen use efficiency when N fertilizer application at180kg/ha and270kg/ha.The PFPN and NHI of ZhongshuangNo.11and ChuannongyouNo.3had’nt significant difference between different application times of nitrogen fertilizer.4. The yield (including the yield of rapeseed and oil) of ZhongshuangNo.11and ChuannongyouNo.3were increased at earlier stage and decreased at later stage with N fertilizer application increased, and obtained higher yield when nitrogen application amount180kg/ha, and the yield had’nt significantly increased when N fertilizer application continuedly increased. ZhongshuangNo.11had higher yield of rapeseed and oil when the N fertilizer as three times application, and ChuannongyouNo.3had higher yield when the N fertilizer as two times application. Total pods of plant and seeds per pod increased with N fertilizer application increased, but the times of N application don’t had significant infection for yield components.5. With N fertilizer application increased, protein content of rapeseed showed a gradually increasing trend and oil content showed a gradually decreasing trend. The rapeseed protein content of ZhongshuangNo.11and ChuannongyouNo.3were highest when the N fertilizer as two times application, respectively22.75%and20.17%. The protein of two kinds of rapeseeds had highest values when N fertilizer was full as basal application, respectively is41.67%and37.50%. Nitrogen fertilizer management don’t had significant infection for fatty acids of rapeseed, but there were significant differences among varieties.Comprehensively consider the yield, quality and nutrient use efficiency of rapeseed, it’s can get higher yield, excellent quality and higher nutrient use efficiency for ZhongshuangNo.11and ChuannongyouNo.3when nitrogen application amount180kg/ha. From the nitrogen application times to analysis, the N fertilizer as one time application can obtain higher yield, and can save labor and production cost.