Influence of integrated weed-management practices on productivity and profitabil- ity of wet-seeded rice (Oryza sativa)

Abstract

A field experiment was conducted at Coimbatore during 2000-2001 and 2001-2002 to study the effect of seeding methods (surface and anaerobic), in-situ incorporation of dhaincha (Sesbania aculeata) and time of pretilachlor-plus application on productivity and profitability of wet-seeded rice (Oryza sativa L.). Treatments in- cluded two seeding methods, viz. surface wet seeding and anaerobic seeding, with two intercropping levels, viz. sole rice and rice + dhaincha; and four weed-control treatments, viz. pretilachlor-plus @ 0.30 kg/ha 2 days after sowing (DAS) followed by (fb) 1 hand-weeding (HW) at 45 DAS, pretilachlor-plus @ 0.30 kg/ha 5 DAS fb 1 hand- weeding at 45 DAS, hand-weeding twice at 20 and 45 DAS, and unweeded check. Surface and anaerobic drill seeding were comparable in terms of weed density, growth and productivity of rice. Conjoint cropping of rice + dhaincha and incorporation of the latter at 37 DAS using con0 weeder proved better in terms of reducing the total weed density, increasing the crop growth, productivity (5.1 tlha) and weed-smothering efficiency (25.5%) of wet- seeded rice. Pre-emergence application of pretilachlor-plus @ 0.30 kg/ha on 2 DAS + hand-weeding at 45 DAS registered lower total weed density (53.6/m2) and higher weed-control efficiency, as well as markedly improved the growth and yield parameters and grain yield (5.6 ttha). Anaerobic seeding, rice + dhaincha and pretilachlor-plus at 2 DAS gave better profit (Rs 13,892lha). It was concluded that anaerobic seeding, dual cultivation of rice + dhaincha and pretilachlor plus @ 0.30 kg /ha on 2 DAS + hand-weeding at 45 DAS is an efficient method for im- proving weed control, productivity and profitability of wet-seeded rice.