R. Nataraj , B.M. Dodamani , S.N. Vinodakumar , B.T. Pujari and V.P. Nagalikar
Abstract
A field experiment was carried out during kharif season of 2009-2010 at the Agriculture College Farm, Bheemarayanagudi, Karnataka (India) to study the response of Bt cotton to different irrigation methods and nutrient levels. Among the irrigation methods significantly highest water use efficiency (WUE) was recorded in alternate furrow irrigation (AFI) + mulching (2.79 kg ha -1 mm) compared to conventional furrow irrigation (2.42 kg ha -1 mm). However, it was on par with alternatively alternate furrow irrigation (AAFI) (2.65 kg ha -1 mm) and alternate furrow irrigation (AFI) (2.61 kg ha-1 ). WUE of Bt cotton differed significantly among nutrient levels. Significantly lower WUE recorded in 75 % RDF (2.29 kg ha -1 mm), which increased significantly to 2.91 kg ha-1 mm in 125 % RDF. Significantly higher NPK uptake was recorded with conventional furrow irrigation (142.83, 37.56 and 161.56 kg NPK ha -1 respectively) compared to AAFI and AFI. However, it was on par with AFI + mulching. Regarding quality parameters irrigation methods had significantly influenced seed index and lint index, whereas, ginning percentage and mean fibre length did not differ significantly due to irrigation methods. Interaction effect of fertilizer levels and irrigation methods were significant on WUE and nutrient (NPK) uptake.