Effects of Seeding Time and Competition Period on Weeds, Growth and Yield of Direct Seeded Fine Rice (Oryza Sativa L.)

The information on combined effect of seeding time and competition period on weeds, phenology and yield of directly sown rice is very limited. Field experiments were conducted for two years during 2008 and 2009 to study these effects. Rice cultivar “Super basmati†was seeded during 1st and 3rd week of June and 1st week of July and weeds were allowed to compete for 15, 30, 45, 60 days after seeding (DAS). Weed free treatment along with a weedy check was also maintained for comparison. Interaction effect of seeding time and competition period was significant. Weed crop competition until 15 DAS gave statistically similar kernel yield to weed free in different seeding times with better yield in plots sown in first week of June during both years. However an increase in competition period from 15 DAS to 30 DAS could not exhibit significant differences. Further increase in competition periods increased the weed density and biomass with significant reduction in yield. So rice may be direct seeded in first week of June and weeds be controlled from 15 to 30 DAS in direct seeded culture in agro physiological conditions of Faisalabad (Pakistan). However more research is needed on checking the competition between weeds and direct seeded rice in terms of density of weeds.