Response of rice to different nitrogen and phosphorous levels under irrigated conditions

A field experiment was conducted at Agricultural Research Station, kampasagar, Nalgonda, Telangana during kharif 2011 & kharif 2012 to study the response of transplanted rice to four levels of Nitrogen (0, 120,160 and 200 kg N ha-1) and four levels of Phosphorous (0,30,60 and 90 kg ha-1). The experiment was designed in Randomized Block Design and replicated thrice. Significantly more number of tillers and panicles were observed at 200 kg N ha-1 than other levels. Panicle length and number of filled grains panicle-1 were significantly higher at 120 kg N ha-1 than 0 kg N ha-1 and it was comparable with 160 and 200 kg N ha-1. Significantly lower sterility percentage was observed at 120 and above levels than 0 kg N ha-1. The grain yield was significantly higher in 120 kg N ha-1 (5069 kg ha-1) than the 0 kg N ha-1 (3730 kg ha-1). The grain yield at upper doses was comparable with that of 120 kg N ha-1. Straw yield was significantly higher at 120 kg N ha-1 than 0 kg N ha-1. Straw yield at higher doses were statistically similar with 120 kg N ha-1. Harvest Index was significantly higher in 200 kg N ha-1 than 120 and 0 kg N ha-1. HI at 160 kg N ha-1 was comparable with both 120 and 200 kg N ha-1. Both in grain and straw 120 kg N ha-1 significantly increased NPK uptake than 0 kg N ha-1. Grain and straw NPK uptake at above levels were comparable with 120 kg N ha-1. P2O5 levels did not show any significant influence on yield attributes, yield and nutrient uptake. High NNG was attained at 120 kg N ha-1 and above doses than control. Reverse trend of NUEPG was obtained with increase in N doses.