Productivity, competition indices and soil fertility changes of Bt cotton (Gossypium hirsutum) – groundnut (Arachis hypogaea) (Gossypium hirsutum) – groundnut (Arachis hypogaea)

Abstract

A field experiment was conducted during rainy (kharif) seasons of 2006 and 2007 to study the productivity, biological feasibility, economic viability and nutrient dynamics in Bt cotton (Gossypium hirsutum L.) - groundnut (Arachis hypogaea L.) intercropping system under various fertility levels. Groundnut as an intercrop enhanced the productivity of cotton by 0.25 tonne/ha. Cotton receiving no N showed superior performance of intercropped groundnut in terms of pods/plant (36.0), kernels/ pod (1.56) and pod yield (0.56 tonne/ha). The mean N, P, K uptake in intercropped cotton were 79.4, 6.6, and 46.0 kg/ha higher than sole cotton (149.9, 16.3 and 80.0 kg/ ha), respectively. Among N management practices, substitution of 25% RDN through farmyard manure in cotton gave the highest system productivity (3.5 tonnes seed cotton equivalent yield/ha), net returns (`50 780) and production efficiency (19.4 kg/ha/day). The highest B: C ratio (2.58) was observed with 100% RDN, followed by 75% RDN + 25% through FYM (2.29). Control treatment gave the highest LER (1.72), RNR (1.37) and ATER (1.47), followed by 50% RDN + 50% through FYM. However, soil NPK balance were in favour of 50% RDN substitution through farmyard manure.