Growth and Yield of Maize (zea Mays L.) as Affected by Row Spacing and Weed Competition Durations

A field experiment was conducted for two consecutive years (2003 and 2004) to study the effect of row spacing (75, 65 and 55cm) and different weed competition durations (0, 15,30,45,60 days after emergence and throughout the growth period) on weeds density and biomass and growth and yield of maize. Reducing row spacing significantly suppressed the weed density and biomass. The maximum reductions in weed density (9 %) and dry weight (34%) were recorded in 55 cm row spacing as compared with 75 cm row spacing. However, the effect of row spacing on maize grain yield was non significant in both years. Weed population and biomass in all weed-crop competition durations was significantly higher than weed free crop and resulted in a considerable reduction in crop growth and yield. The maximum reduction in crop growth rate (38%), leaf area index (44%) and grain yield (51%) were recorded in full season weed-crop competition as compared with weed free crop. The row spacing of 55 cm in maize was effective in suppressing weeds and the maximum weed density and biomass at 30 days after emergence indicate the need of early weeding in maize.