Resource Use Efficiency, Productivity and Profitability of Bt Cotton (interspecific) as Influenced by Crop Geometry and Drip Fertigation

Background: Cotton is one of the important commercial crops cultivated in India for fibre and oil. The average cotton productivity of India is lower compared to other countries. Among the improved agronomic practices, important yield contributing agro techniques are crop geometry and fertilizer application. Drip irrigation and use of water soluble fertilizers (WSF) by drip system is a recommended practice to increase both water and nutrient use efficiency. Taking this aspect, a field investigation was carried out to find the resource use efficiency, productivity and profitability of inter specific Bt cotton hybrid with different levels crop geometry and drip fertigation.Methods: A field experiment was conducted at TNAU, Coimbatore during 2013 and 2014 for two consecutive years. The experiment was laid out in a strip plot design with three replications. The treatments in main plot consisted of four crop geometry levels (120 x 60 cm, 120 x 90 cm, 150 x 60 cm and 150 x 90 cm) and sub plots consisted of four nutrient levels viz., 75 %, 100 %, 125 % of recommended dose as water soluble fertilizer (WSF) through drip system and as conventional practice. Resource use efficiency (water, nutrient), seed cotton yield and profitability of the system were recorded.Result: The experiment revealed that the fertilizer use efficiency and the efficiency of individual nutrient (partial factor productivity) for the crop geometry of 120 x 90 cm and 75% RDF were higher in both the years. The crop geometry of 120 x 90 cm in combination with 125% RDF effectively utilized the water as indicated by its water use efficiency and comparable results was also obtained with 100% RDF. The mean (2012-13 and 2013-14) seed cotton yield of 2,713 kg ha-1 in 120 x 90 cm kg ha-1 for 125% RDF was 41.5 per cent higher compared to their lower counterpart. Their interaction was significant, consequently the treatment M2S3 (120 x 90 cm and 125% RDF) recorded higher mean (both years) seed cotton of 3,176 kg ha-1 which was nearly 93.7 per cent increase over conventional irrigation and fertilizer application (M4S4). Here M1S2 could be considered as alternate option as it maintained similarity with the best treatment. The gross and net return was estimated to be higher with spacing of 120 x 90 cm with 125 % RDF and however the benefit cost ratio was higher with 120 x 90 cm with 100 % RDF followed by 120 x 60 cm with 100 % RDF.