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 (6th July, 21st July and 5th 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. 21st 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 5th August transplanting. Transplanting
either on 6th July or 21st July produced significantly higher grain and straw NPK
uptakes, agronomic efficiency and partial factor productivity of nitrogen than late
transplanting on 5th 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 21st 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
