Abstract

Field experiments were conducted at Cotton Research Station, Veppanthattai during 2012–13 and 2013–14 to carry out the studies on tillage with crop residues and supplemental irrigation through drip system on rainfed Bt cotton. The experiments were laid out in a strip plot design with three replications. The main plot treatments were conventional tillage, minimum tillage without crop residue, minimum tillage with crop residue @ 2.5 t/ha and minimum tillage with crop residue @ 5 t/ha. Conventional tillage comprised one disc ploughing, four cultivator ploughings and two harrowings (0.3–0.4 m deep). Minimum tillage included only one ploughing (cultivator) and two harrowings (0.1–0.12 m deep). The sub-plot comprised irrigation treatments viz., supplemental drip irrigation through drip system one, two and three times and without irrigation (control) during the cropping period. Under paired row planting system (120+30 x 60 cm spacing), one 12 mm lateral was laid out between two rows of Bt cotton. The supplemental irrigations were given to the crops at the time of moisture stress period determined based on the visual symptoms of wilting. Recommended dose of fertilizers viz., 120: 60: 60 kg NPK/ha was applied to Bt cotton. The results revealed that minimum tillage (BBF) with crop residue application @ 5 t/ha (M4) recorded higher plant height, dry matter production, LAI, number of sympodial branches/plant, number of bolls/plant and seed cotton yield.