Impact of Site Specific Nitrogen Management on Growth Parameters, Productivity and Profitability of Kharif rice

A field experiment was carried out during kharif 2021 (June-November) and 2022 (June-November) at the Agronomy Main Research Farm, Department of Agronomy, College of Agriculture, OUAT, Bhubaneswar. The experiment was laid out in randomized complete block design with twelve treatments i.e. T1-RDF (80:40:40 kg N:P2O5:K2O ha-1), T2 - 20 kg N ha-1 at LCC score <4 with no basal N, T3 - 20 kg N ha-1 at LCC score <4 with 20 kg N ha-1 at basal, T4 - 20 g N ha-1 at SPAD value <35 with no basal N, T5- 20 kg N ha-1 at SPAD value <35 with 20 kg N ha-1 at basal, T6- 20 kg N ha-1 at Green seeker (GS) >1.25 RI with no basal N, T7- 20 kg N ha-1 at Green seeker (GS) >1.25 RI with 20 kg N ha-1 at basal, T8- 150 kg N ha-1 (N rich strip plot), T9- N omission plot, T10- STBN, T11- INM (20 kg N ha-1 as FYM at basal + 40 kg N ha-1 at tillering + 20 kg N ha-1 at PI stage), T12- Organic nutrient (FYM 10t ha-1 at basal + 2t ha-1 VC top dressing). Pooled analysis revealed that application of 20 kg N ha-1 at Green seeker (GS) >1.25 RI with 20 kg N ha-1 at basal recorded maximum dry matter accumulation (1194.1 g m-2), larger leaf area index (3.30), highest number of tillers (381 m-2) at harvest and maximum CGR of 18.73 g m-2 day-1 during 60 to 80 DAT followed by the treatment receiving 20 Kg N ha-1 at SPAD value <35 with 20 Kg N ha-1 at basal. Combined analysis of both years showed that application of 20 kg N ha-1 at Green seeker (GS) >1.25 RI with 20 kg N ha-1 at basal recorded significantly higher grain yield (5.68 t ha-1), straw yield (6.57 t ha-1) and harvest index (47 %) with maximum net return 55982 Rs ha-1 and B:C ratio 1.82.