Abstract: The aim of the study was to obtain optimal nitrogen (N) fertilizer management techniques of winter rapeseed for high yield and high quality under the condition of direct-sown by machine. Two field experiments were conducted in Chengdu Plain of Sichuan Province under a rice-rapeseed rotation system. The effects of different N applied rates (0,90,135,180,225 kg/ha) in the same N application method and different N application method (single application of basal fertilizer,twice application of a basal fertilizer and a top dressing,three times of application as a basal fertilizer and two top dressings) in the same N rate (180 kg/ha) on agronomic traits,yield,quality and nitrogen fertilizer used efficiency of rapeseed Chuanyou 36 were studied.The results showed that the effects of N fertilizer management on agronomic traits,yield,quality and nitrogen fertilizer used efficiency in rapeseed were significant.Seed yield was improved with the increase of N rates (0-225 kg/ha) and high yield level (≥ 3 000 kg/ha) were obtained by N135,N180 or N225 treatment. There was an obvious trend of decrease in seed oil percent,but increase in protein percent with the increased in N applied rates. With the increased in N applied rates (90-225 kg/ha),agronomic efficiency of applied N fertilizer (27.9-15.0 kg/kg) and partial factor productivity from applied N fertilizer (29.2-15.6 kg/kg) of rapeseed were obviously or notably decreased and increased for N fertilizer contribution rate (37.2%-52.5%). No significant difference of seed yield,seed oil percent and protein percent of rapeseed were observed. Therefore,The rate of N 135-180 kg/ha and single basal or twice application of a basal fertilizer and a top dressing are suitable nitrogen fertilizer management techniques for high yield and high quality of rapeseed Chuanyou 36 under the condition of high density and direct-sown by machine and moderate soil fertility of Chengdu Plain in Sichuan Province.

Key words: Winter rapeseed, Direct-sown by machine, Nitrogen fertilizer management, Yield, Quality, Nitrogen fertilizer use efficiency

CLC Number: 

• S143.1