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.