Exhausting weed seed bank before sowing through stale seedbed technique for managing weeds in winter irrigated Bt cotton (Gossypium hirsutum) based intercropping system

摘要

A new method of introducing short duration less aggressive weed smothering intercrop which could complete the life cycle within 40 - 45 DAS without sacrificing the main crop population was standardized. Weed control under intercropping system is cumbersome and the removal of weeds by manual method is tedious as it is very difficult to differentiate the young weed seedlings and germinating intercrops. Hence, a novel approach of exhausting weed seed bank before the crop emergence by stale seed bed approach was standardized for Bt cotton based intercropping system during 2010-2011 and 2011-2012 cropping season at Regional station of Central Institute for Cotton Research, Coimbatore. Among the treatments, Stale Seed Bed Technique (SSBT) using a mixtureof pendimethalin 1.0 kg + glyphosate 1.0 kg one week after pre sowing irrigation (one week before sowing) recorded the highest weed control efficiency of 85.2 per cent on 35- 40 DAS. Adopting this new method of planting, Bt cotton RCH 20 Bt with coriander as intercrop under SSBT method of managing weeds with pendimethalin 1.0 kg + glyphosate 1.0 kg recorded the highest seed cotton yield (3261 kg/ha) and seed cotton equivalent yield (4686 kg/ha) .