ABSTRACT
The effectiveness of various herbicide treatments for season-long control of weeds in three cultivars of rice (Oryza sativa L) was investigated in 1983 wet and 1983-84 dry seasons at Badeggi (09Â 45'N and 06Â 30'E,, 70.5m above mean sea level) in the Southern Guinea Savanna ecological zone of Nigeria. During the 1986 wet and 1985-86 and 1986-87 dry seasons, field trials were conducted to evaluate herbicide combinations for the control of cutgrass (Leersia hexandra Swartz Prod) in direct-seeded lowland rice. The rice cultivars consisted of FARO 15, FARO 27 and FARO 29 which were tall, short and of medium height, respectively. The rice cultivars had significant effect on weed infestation at crop harvest and on qrain yield. Plots sown with FARO 27 consistently had the highest infestation of weeds in the two seasons. In 1983 wet season, FARO 15 and FARO 29 resulted in similar grain yields that were significantly higher than that of FARO 27. However, in the 1983-84 dry season, FARO 29 produced higher grain yield than FARO 15 and FARO 27 which were similar in grain yield. The effect of weed control treatments on weed infestation, % weed coveraqe was also significant as reflected in dry weed weight at 30 and 60 days after vi
