Effect of Weeding Time on Rice (Oryza sativa Linn) Yield and Yield Components at Kaffa, Southwest Ethiopia

Abstract

Weeds are major constraints to rice production in labor-limited, upland rice-based systems in Kaffa zone, Southwestern Ethiopia. The effects of weeding time on yield and yield components of two upland rice cultivars; Nerica 4 and Superica 1 was investigated at Gojeb testing site of Kaffa zone in 2009/2010 cropping season. The experimental treatments were weeding at 15-20+30-35+45-50 days after emergence (DAE), 20-25 +35-40 +50-55 DAE, 30-35+45-50+60-65 DAE and farmers practice (weeding at 20-25 DAE once) as control check. Moreover types of weed species are recorded. Based on the result dominant weed species observed on rice filed were Digitaria abyssinica, Phalaris paradoxa, Setaria pumila, Hygrophila auriculata, Amharanthus caudatus, Commelina latifolia, Xanthium spinosum, Cynodon nlemfuensis and Cyperus assimilis. ANOVA result shows that different weeding times affected significantly (p < 0.001) grain yield and yield components of both rice varieties. The maximum grain yield (44.18 and 63.82 Q/ha) was obtained when weeding made at 15-20+30-35+45-50 DAE while the minimum value (21.36 and 31.63 Q/ha) observed from weeding at 30-35+45-50+60-65 DAE for Superica-1 and Nerica-4 rice verities respectively. Moreover, maximum 1000 grain weight, straw yield and tillers number of rice were recorded upon weeding at 15-20+30-35+45-50 DAE. There for early weeding have significant roll on rice yield and yield components.

Keywords:  rice, weeds, weeding time, yield and yield components