Title: Response of Hybrid Rice to Transplanting Date and Nitrogen Fertilization under System of Rice Intensification in Rainfed Lowland Ecosystem
Abstract: A field experiment was conducted during kharif seasons of 2011 and 2012 at Imphal, Manipur to study the performance of hybrid rice PAC-801 to transplanting dates (6 th July, 21 st July and 5 th August) and nitrogen levels (0, 60, 120 and 180 kg N ha -1 ) on productivity, profitability and nitrogen use efficiency under system of rice intensification in rainfed lowland condition.21 st July transplanted hybrid rice significantly increased panicles m -2 (17.9%), panicle length (4.6%), spikelets panicle -1 (13.7%), filled grains panicle -1 (17.7%), 1000-grain weight (2.17%), grain yield (12.4%) and straw yield (8.6%) over 5 th August transplanting.Transplanting either on 6 th July or 21 st July produced significantly higher grain and straw NPK uptakes, agronomic efficiency and partial factor productivity of nitrogen than late transplanting on 5 th August.Hybrid rice PAC 801 showed significant response to application of N up to 180 kg N ha -1 which improved the yield attributes (panicles m -2 , panicle length, spikelets panicle -1 , filled grains panicle -1 ), grain and straw yields and NPK uptakes of grain and straw.Maximum grain yield (7,169 kg ha -1 ) was with 180 kg N ha -1 .This was 32.8, 13.3 and 2.2% higher over 0 (control), 60 and 120 kg N ha -1 , respectively.Nitrogen fertilization beyond 60 kg ha -1 level significantly reduced agronomic efficiency, partial factor productivity and apparent recovery of applied nitrogen.Transplanting hybrid rice on 21 st July along with nitrogen fertilization of 120 kg ha -1 resulted higher economical grain yield under rainfed lowland ecosystem as compared to rest of the treatments.