ABSTRACT

 A field study was carried out during the 2005 dry and 2006 rainy seasons at the research farm of the Michael Okpara University of Agriculture, Umudike to determine the effect of crop density and weed control methods on weed growth and yield of okra in Umudike. Results of the experiment showed that in both years, okra density did not have significant effect on weed density and periodicity of weed seedling emergence. However, reduction in weed density and weed seedling emergence was higher in plots with high okra density (166,666.6 plants/ha). Results also showed that weed dry matter in both years were lowest in the 30 cm x 20 cm (166,666.6 plants/ha) narrow rows (high density) compared to the 30 cm x 40 cm (88,888.8 plants/ha) wide rows (low density). In both years, plots having high okra density performed better than other densities though not significantly, in encouraging good growth and yield of okra. In both years, among the weed control methods, significant reduction in weed growth was obtained in plots treated with codal pre-emergence herbicide at 3.5 1/ha and 51/ha (1.75 kg a.i./ha and 2.5 kg a.i./ha respectively). Result also showed that there was no significant difference in weed control between the 2 herbicide rates in both years. Weed growth was highest at 3 weeks after planting (WAP) in 2005 dry and at 2 WAP in 2006 wet season in plots weeded once. In 2005, plots weeded once gave the best yield of okra compared to other weed control methods. However, in 2006, the highest okra yield was obtained in the weed — free plots while the least yield was obtained in the unweeded plots. The results suggest that in the dry season, higher okra density may be integrated with one hoe weeding at 3 WAP to achieve significant reduction in weed growth and higher okra yields, while in the rainy season the same goals may be attained if higher okra density is integrated with lower rates of herbicide and one hoe weeding at 4WAP to keep other emerging weeds below the economic threshold of infestation.