Effect of weed mangement and sulphur on weed count, growth attributes and yield of soybean (Glycine max)

A field experiment entitled “Effect of weed mangement and sulphur on weed count, growth attributes and yield of soybean (Glycine max) ” was conducted during kharif seasons of 2011 and 2012 at Instructional Farm (Agronomy), Rajasthan Collegeof Agriculture, Udaipur. The study involved 28 treatment combinations, comprising 7 weed control treatments (weedy check, pre-emergence application of pendimethalin at 1000 g/ha, post-emergence application of quizalofop-ethyl at 50 g/ha and imazethapyr at 100 g/ha at 15 day after sowing alone and followed by hoeing & weeding at 30 DAS) and four levels of sulphur (control, 20, 40 and 60 kg/ha). The treatments were replicated thrice. All weed control treatments reduced weed count over weedy check on pooled basis. Pendimethalin followed by hoeing & weeding at 30 DAS was significantly superior in reducing weed count of broad-leaved and total weeds at 25 and 50 DAS over rest of the treatments but quizalofop-ethyl fb hoeing & weeding was significantly superior in reducing weed count of narrow-leaved weeds at 25 and 50 DAS. Pre-emergence application of pendimethalin fb by hoeing & weeding gave maximum branches/plant and dry matter of crop followed by imazethapyr and quizalofop-ethyl POE fb hoeing & weeding. All weed control treatments significantly enhanced seed yield of soybean over weedy check. Pendimethalin followed by hoeing & weeding at 30 DAS produced significantly higher pooled seed (2168 kg/ ha) yield compared to other treatments. All the weed control treatments and sulphur levels did not differ significantly in their effect on plant population of soybean at 20 DAS and at harvest on pooled basis. Sulphur rates had no significant effect on weed count at 25 and 50 DAS. The plant height increased significantly by applying 20 kg S/ha while number of branches/plant increased significantly by up to 60 kg S/ha. Application of 40 kg S/ha resulted in significantly higher crop dry matter at 25 and 75 DAS but results were significant only up to 20 kg S/ha at 50 DAS and harvest. Significantly higher seed (1892 kg/ ha) yield of soybean was obtained by applying 40 kg S/ha.