Weed suppressiom and production potential of direct- seeded puddled rice (Oryza sativa) as affected by herbicides under varying water management practices

A field experiment was conducted for two consecutive kharif seasons of 2003 and 2004 at Kanpur to assess the relative efficacy of herbicides under varying water management practices in direct seeded puddled rice (Oryza sativa L.). Results revealed that anilofos (0.45 kg/ha) reduced density of Cyperus iria and Echinochloa colona by 76.2 and 58.7% at 30 days after sowing (DAS), and 61.8 and 57.3% at 90 DAS, respectively, resulting in 50.6% increased in grain yield over untreated. Butachlor (1.5 kg/ha) controlled grasses appreciably but was less effective against broad-leaved weeds and sedges at 30 and 90 days after sowing. Metsulfuron-methyl + chlorimuron-ethyl (4 g/ha) provided excellent control of broad-leaved weeds. Further, anilofos (0.45 kg/ha) applied at 7 DAS reduced weed dry-matter accumulation significantly which obtained 52 and 55% weed control efficiency during both the stages, resulting in enhanced yield attributes viz., effective panicles/m² (60.9/m²), panicle length (2.79), grains/panicle (12.86), 1000-grain weight (2.86 g) and finally grain yield (1.115 tonnes/ha) over that of untreated. Spraying of herbicides in presence of standing water proved to be optimum condition for intended weed control during both the years of study.