A field experiment was carried out at University of Agricultural Sciences, Dharwad for two years (2012-13 and
2013-14) on effect of nitrogen levels and potassium ratios on growth, yield and economics of Bt cotton. The experiment was laid out
in Randomized Block Design (factorial) with three replications. Three nitrogen levels viz., N1: 120 kg N ha-1, N2: 150 kg N ha-1 and
N3:180 kg N ha-1 and Four potassium nitrogen ratios (K:N) i.e., K1: 0.25, K2: 0.50, K3: 0.75 and K4:1.00. Application of 180 kg
N ha-1 recorded significantly higher seed cotton yield (3249 kg ha-1), Seed cotton yield per plant (207.1 g), total dry matter
production (294.5 g plant-1), higher gross returns (`146222 ha-1), net returns (` 97, 765 ha-1) and B: C ratio (3.01) over other
nitrogen levels. K:N ratio of 1.00 recorded significantly higher seed cotton yield (3223 kg ha-1), seed cotton yield per plant
(208.7 g), total dry matter production (298.1 g plant-1), higher gross returns (` 145026 ha-1), net returns (` 96,166 ha-1) and B:
C ratio (2.96 ha-1) as compared to other K:N ratios, However, it was on par with 0.75 K:N ratio. Application of 180 kg N
ha-1 with K;N ratio of 1.00 (180 : 180 kg NK ha-1) recorded significantly higher seed cotton yield (3501 kg ha-1), net returns
(` 1,06,523ha-1) and B:C ratio (3.08).