Yield Loss Due to Weed Interference and Economic Evaluation for Weed Control Methods in Faba Bean and Chickpea Crops

Abstract

Four field experiments were conducted in Sids Agricultural Research Station to study the response of faba bean and chickpea crops to various weed densities as well as the economic feasibility of weed control methods, two experiments for each crop were conducted during 2005/06 and 2006/07 winter seasons.Both faba bean and chickpea yields were inversely proportional to weed density, the minimum weed density which faba bean and chickpea can tolerated it equal 15 and 10 weeds/m 2 which cause 2 and 3% yield reduction, respectively. Meanwhile, weed density level which exert yield losses exceeded 50% equal 360 weeds/m 2 or 400 plants/m 2 from canary grass in faba bean crop, 210 weeds/m 2 or 250 plant/m 2 from canary grass in chickpea crop, respectively. Economic threshold where the cost of weed control inputs equal financially the gained yield of weed control was at 8, 20, 42 and 9, 22 and 60 (weed density/m 2 ), for Fusilade, hand hoeing and Gesagard + Fusilade treatments in the same respective. Depending on these results chickpea considered more susceptible to weed competition than faba bean where the corresponding values of weed density which cause 2%, yield losses or the highest potential yield losses 73 and 100%, respectively.All weed control treatments either by mechanical or chemical by Gesagard at 1.5 l/fed or Gesagard at 1.5 l/fed pre emergence +Fusilade super at 500 cm 3 /fed post emergence and Gesagard at 1.5 l/fed pre emergence+ Select super at 250 cm 3 /fed. post emergence caused yield increases exceeded the economic threshold levels in faba bean and chickpea crops.Thus, the estimation of weed density can be used to predict faba bean and chickpea seed yield loss due to weed competition which help in making rationale decisions for weed control by hand hoeing, Gesagard, Gesagard+ Fusilade super or + select super at mentioned rates per feddan, in these crops.