Abstract:Two field experiments were carried out to explore the effects of single and combined application of controlled release coated urea and conventional urea on yield and nitrogen fertilizer use efficiency of direct sowing rapeseed (Brassica napus L.) at a paddy field in Chengdu plain. During the period from 2011 to 2012, three experiments were conducted with controlled release coated urea (CU), conventional urea (PU), and 1︰1 of coated urea and conventional urea (PCU)) at the same N fertilizer amount (189 kg/hm2) in form of single basal application. During the period from 2012 to 2013, six experiments were set up, they were combined application of conventional urea and controlled–release coated urea the ratio of 33%, 50% and 67%, labeled by PCU33, PCU50 and PCU67 respectively; single basal application (T1), basal application and one time topdressing (T2) at the same N fertilizer amount (180 kg/hm2).The results indicated that seeds yield(316 6.9 kg/hm2), agronomic efficiency of N fertilizer (AEN, 8.0 kg/kg), partial factor productivity of N fertilizer(PFPN,16.8 kg/kg), N fertilizer contribution rate(NCR, 47.9%)and apparent recovery efficiency of N fertilizer(REN, 54.5%)in treatment PCU were relative higher than that in treatment PU at the same amount of N application (189 kg/hm2). Seed yields in treatment PCU33 and PCU50 were 162 9.0 and 182 0.1 kg/hm2, respectively, which were obviously higher than that in treatment PCU67 at the same amount of N application (180 kg/hm2), the same situation was true for nitrogen fertilizer use efficiency in treatments PCU33 and PCU50 compared with treatment PCU67. Therefore, combined application of 33% to 50% controlled release coated urea as single basal application could be beneficial to high yield and use efficiency for direct sowing rapeseed in Chengdu plain.