Effects of land preparation practices and spacing on weed growth and yield of upland rice (Oryza sativa L.)
Effects of four tillage practices and spacing on weed growth, seedling establishment and yield of an upland rice cultivar (FARO 11) were evaluated in two field experiments at the University of Ilorin Teaching and Research Farm in 1994 and 1995. Crop establishment and grain yield were lower in minimally tilled than in conventionally tilled soil. T.he poor rice yield in the minimally tilled plot was attributed partly to weed infestation and poor crop establishment. The number of filled grains per panicle of rice was significantly higher in minimum than in conventional tillage plots suggesting that significant yield increase of upland rice is attainable with minimum tillage practices. There were however indications that such yield improvement is obtainable if weeds are adequately controlled and optimum crop stand is ensured. Row spacing of 20cm x 20cm, 25cm x 25cm, and 30cm x 30cm suppressed weed growth better than the 40cm x 40cm spacing. Grain yield was highest with 30cm x 30cm spacing and lowest with 40cm x 40cm spacing.