Productivity and nutrient uptake of Bt-cotton (Gossypium hirsutum) as influenced by precision in application of irrigation and fertilizer

Drip irrigation and fertigation has much scope in increasing the productivity of water and yield per unit area. Therefore, present field experiment was conducted from 2007-08 to 2009-10 at Akola (Maharashtra) to compare irrigation based on crop evapo-transpiration (Etc) and fertilizer through drip system against conventional irriga- tion and fertilizer application methods in Bt-cotton hybrid ( Gossypium hirsutum L.). Results indicated that sched- uling of irrigation at 1.0 Etc and application of 125% recommended dose of fertilizers (RDF) (125: 62.5: 62.5 kg NPK/ha) through drip, recorded highest seed cotton yield (2.17 t/ha), which was at par with 0.8 Etc with 125% RDF (2.02 t/ha). The yield enhancement due to drip system was 10.53, 11.49 and 12.39 % at 0.6, 0.8 and 1.0 Etc. respectively when compared with application of irrigation at 0.6 IW/CPE ratio. The water requirement at 0.6, 0.8 and 1.0 was 75.8, 96.4 and 177.7 mm/ha respectively, compared to 183.6 mm/ha under 0.6 IW/CPE ratio. Uptake of N, P and K was found maximum with irrigation applied at 1.0 Etc. along with 125% RDF (125:62.5:62.5 kg NPK/ha).