Abstract

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Ginger (Zengeber officinale) is one of the leading exported spice crop in Ethiopia. Weeds are a major constraint in ginger production. Ginger was found very poor competitor of weeds that as weeding was delayed tremendous yield loss was incurred. When weeding was totally ignored yield loss amounted to 100%. Understanding the critical period for weed competition and weed management techniques can be a tool for effective weed control and reducing the impacts of weeds. The experiment was conducted during 2010 to 2012 using randomized complete block design with three replications to determine the critical period and evaluation of weed management techniques at Tepi in south west Ethiopia. Timing of weed removal was based on the number of days after ginger planted. To determine critical time of weed competition, weeds allowed competing with ginger for 15, 30, 45, and 60 days after planting. In addition, season long weedy check and weed-free check were included as control. For weed management study five treatments (mulching at planting + weeding at 45, and 75 days; mulching at planting + weeding at 60 and 90 days; weeding at 30 + mulching + two hand weeding as needed; weeding at 30, 60 + mulching + one hand weeding as needed; weeding at 45, 75 + mulching + one hand weeding as needed) were applied which contain both hand weeding and mulching at different periods. All noxious and important weed species were abundantly grown in the experimental site and the surrounding, the important weeds were Poaceae and Asteraceae. Number of tiller, number of leaf per tiller, plant height, leaf width and length, rhizome width and length, number of fingers per rhizome and yield were affected significantly at p<0.001. Maximum yield loss (47%) was recorded when weeding applied at 60 days after planting (DAP) but minimum yield loss (9%) at 30 DAP. Yield advantage of 41% and 34% obtained when first hand weeding was applied at 30 and 45 DAP respectively as compared to 60 DAP. Sever ginger-weed competition was taken place between 30 and 60 days. Mulching of ginger after one or two hand weddings at 30 and 45 DAP found as good agronomic practice. plant height, leaf length, leaf width and weed biomass were do have a significant negative association with that of ginger yield where as number of ginger tiller per plant, number of leaf per tiller, rhizome length and width, number of fingers per rhizome, and stand count were found a positive significant association with yield. Hence, it would be wise to apply the first hand weeding between 30 and 45 DAP in order to avoid sever competition for maximum yield of the crop.

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