Grain yield, nutrient use efficiency and economics of aerobic rice (Oryza sativa L.) as influenced by different levels of NPK in Cauvery Command Area

Field experiment was conducted during kharif seasons of 2004 and 2005 at Zonal Agricultural Research Station, V. C. Farm, Mandya, Karnataka to study the different levels of NPK on growth and yield of aerobic rice in Cauvery Command area. The research results revealed that application of 125 kg N/ha recorded significantly higher grain yield (7.26 and 7.23 t/ha) and net monetary returns (Rs. 26487/ha). Among phosphorus levels, 62.5 kg P2O5/ha recorded significantly higher grain yield (7.10 and 7.14 t/ha) and net monetary returns (Rs. 25826/ha). Higher grain yield (7.26 and 7.21 t/ha) and net monetary returns (Rs. 26553/ha) were noticed with 62.5 kg K2O during the years 2004 and 2005, respectively. The nutrient use efficiency was higher with 75 kg N/ha (36.13 and 36.50 kg grain/kg NPK), 37.5 kg P2O5 (35.54 and 35.59 kg and 35.64 kg grain/kg NPK) and 50 kg K2O/ha (36.11 and 35.78 kg grain/kg NPK) which was on par with 100 kg N (36.07 and 35.97 kg grain/kg NPK), 50 kg P2O5(35.24 and 35.23 kg grain kg/NPK) and 37.5 kg K2O/ha (34.06 and 34.77 kg grain/kg NPK) during the years 2004 and 2005, respectively. The benefit : cost ratio was higher with 100 kg N/ha (2.51), 50 kg P2O5/ha (2.46) and 50 kg K2O/ha (2.51).