Critical Crop-Weed Competition Period and Yield Loss Determination in Transplanted Tomato (Lycopersicon esculentum M.) at Guder Ethiopia.

Abstract

A field experiment was conducted for two consecutive cropping seasons of 2013 and 2014 to determine the critical period of weed competition and yield loss in tomato at Guder, Ethiopia. Quantitative series of both increasing duration of weedy and weed free period were compared with complete weed free and weedy check. The experiment comprised of fourteen treatments laid was in RCBD with three replications. Two years pooled data revealed that, Amaranthus spp, Amarathus hybridus L., Bidens pilosa L., Commelina benghalensis L.,Datura stramonium L.,Guizotia scabra (Vis). Chiov., Galinsoga parviflora Cav.,Ipomea cariocarpa and Nicandra Digitaria abyssinica (A. Rich). Stapf and Cyperus esculentus L., were the grass and sedge weeds respectively. Significn difference in density, weed dry biomass, tomato yield and relative yield loss were observe in all the two years. Uncontrolled weed growth caused a yield reduction of 87.5%, 90.80% in 2013 and 2014 respectively, in yield as compared to weed free condition. Results indicated that to prevent greater than 10% yield loss, the maximum time for which weeds could be allowed to grow after crop transplant was 30 days, and the crop must be free of weeds from 60-75 days after transplanting to prevent a predetermined level of yield loss.