Response of soybean cultivars to weed control treatments

Two field experiments were conducted in two successive seasons, 2015 and 2016, at the experimental farm of the National Research Centre at Nubaria, Egypt, during summer seasons to determine weed management can improve soybean competitiveness with weeds, thus helping to achieve its yield potential. The experiment included three soybean cultivars ( Giza 111, Giza 21 and Crawford) and six weed control treatments, including oxadiargyl, butralin, metribuzin, bentazone + clethodium, two hand and a nonweeded treatment (control). Great reduction in dry weight of broadleaved, grassy and total weeds after 60 and 90 days from sowing was noticed in the plots cultivated with Giza 111 cultivars. Also, Giza 111 cultivars markedly produced greater plant height, SPAD, NAR, SLA, LWR and RGR at 60 and 90 days from sowing as well as yield, yield attributes and chemical composition of soybean seeds. Two hand hoeing achieved the highest weed depression expressed in the lowest dry matter of broadleaved, narrow-leaved and total weeds. Also, two hand hoeing was the most superior treatment in increasing plant height, SPAD, NAR, SLA, LWR and RGR at 60 and 90 days from sowing as well as yield, yield attributes and chemical composition of soybean seeds. Two hand hoeing or herbicide bentazone + clethodium integrated with Giza111 cultivar produced the maximum values of plant height, NAR, seed yield and oil percentage. It could be concluded that two hand hoeing or herbicide bentazone + clethodium combined with Giza 111 cultivars recorded effectively improve growth and productivity of soybean under sandy soil condition