Productivity, nutrient uptake and nitrogen–use efficiency of Bt. cotton (Gossypium hirsutum) in relation to split and foliar application of nitrogen on Inceptisol

A 2-years field experiment was carried out at Rahuri from 2011 to 2012 on an Inceptisol soil having 147 kg/ha available N, to study productivity, nutrient uptake and nitrogen-use efficiency of Bt. Cotton (Gossypium hirsutum L.) as affected by split and foliar application of nitrogen. In Bt. Cotton, 10 treatments comprising nitrogen–management practices (application of recommended dose of N in 3, 4, 5, 6 splits; foliar application of 20 g KNO₃/litre water, 20 g urea/litre water, combination of split application of N and foliar spray of 20 g KNO₃/litre water, 20 g urea/litre water and control) were tested on inceptisol. Results indicated that application of N in six splits (20% at sowing as basal and remaining in 5 equal splits at 30, 45, 60, 75 and 90 DAS) recorded significantly higher plant height, sympodial branches/plant, dry-matter/plant, bolls/plant, seed cotton yield/plant, seed cotton yield (66% more than control), higher gross, net monetary returns, benefit: cost ratio, higher uptake of nutrients (N, P and K) and higher agronomic nitrogen–use efficiency. N application in 3 equal splits (at sowing, 30 and 60 DAS + foliar application of 20 g KNO₃/litre water at 60, 75 and 90 DAS) recorded significantly higher boll weight. The physiological nitrogen–use efficiency was found higher with the N application in 3 equal splits (at sowing, 30 and 60 DAS + foliar application of 20g urea/litre water at 60, 75 and 90 DAS).