Field experiments were conducted during Kharif season for two consecutive years of 2008-09 and 2009-10 with rice at Experimental Farm, Annamalai University, Annamalai Nagar (Tamil Nadu), India on deep clay soil (Typic Haplusterts) to study the impact of inorganic and organic nutrient sources and levels on yield, N uptake and its use efficiency in rice under SRI and conventional system of cultivation (CSC). The experiments were conducted in split plot design with two methods of cultivation (SRI and conventional) as main plot treatments and twelve sub plot treatments viz., three inorganic alone applied treatments (100 % RDF, STCR based RDF, LCC based N (Recommended dose of fertilizer P&K without basal N), nine integrated nutrient management treatments (STCR based IPNS , based on 100 % RDF two levels of fertilizer nitrogen (75and 50 per cent) in combination with two levels of N (25 and 50 per cent) through different organic manures viz., Farmyard manure (FYM), Green manure (GM), Pressmud (PM), Poultry manure (POM) as sub plot treatments. The results revealed that the highest grain yield (4661.1 kg ha-1) and straw yield (6708.6 kg ha-1), higher N uptake in grain (46.3 kg ha-1) and lower N uptake in straw (42.5 kg ha-1) in SRI as compared to CSC(4201.5,6367kg ha-1 and 39.2,46.1kg ha-1,respectively),and higher N use efficiency in SRI (ANUE-24.7 %, NER-134.7 kg kg-1, NHI- 49.8 % and NP-1.00 kg kg-1day-1) over CSC(22.5 %,130.6 kg kg-1,43.9 and 0.97 kg kg-1day-1, respectively. Yield of grain (6507.4, 5774.1 kg ha-1) and straw (8211.8, 7643.7 kg ha-1), N uptake in grain (68.3,56.8 kg ha-1) and straw (54.1,58.7 kg ha-1), and N use efficiency(ANUE-45.2,40.1%,NHI- 55.1,48.5 %) were found be significantly higher and lower NER-120.3,116.2 kg kg-1, NP-0.89,0.86 kg kg-1day-1 due to the application of STCR based IPNS (144:64:60 kg NPK ha-1 along with 12.5 t ha-1 FYM and bio-fertilizers viz., Azospirillum and PSB) treatment under SRI and conventional system of cultivation, respectively. N uptake showed highest significant positive relationship with grain and straw yields, and ANUE, NHI and negative relationship with NER and NP under both system of cultivation. Hence, the STCR based IPNS (144:64:60 kg NPK ha-1 along with 12.5 t ha-1 FYM and bio-fertilizers viz., Azospirillum and PSB) can be regarded as the best nutrient management practice under SRI and conventional system of cultivation for enhancing rice yield, N uptake and use efficiency in Cauvery deltaic zone of Tamilnadu.
