Sequential application of metribuzin on weed control, growth and yield of soybean (Glycine max)

A field experiment was conducted for two years at New Delhi to evaluate sequential applications [pre-emer-gence followed by (fb) post-emergence] of metribuzin on weed control in soybean [Glycine max (L) Merrill]. Results indicated that metribuzin at 0.5 kg/ha as pre-emergence resulted in more suppression of Trianthema portulacastrum L., Cyperus rotundus L. and grasses, and caused a significant reduction in total weed population and dry weight. Highest weed control efficiency (WCE) of 83.6% and 73.9%, respectively at 40 and 60 days after sowing (DAS) was resulted from this treatment followed by metribuzin 0.25 kg/ha pre-emergence fb 0.1 kg/ha at 20 DAS with volume rate of 200 l/ha. Metribuzin 0.25 kg/ha pre-emergence fb metribuzin (0.1 kg/ha, 200 l/ha, 20 DAS) was the next best combination resulting higher soybean yield through concurrent reduction in weed growth. Excluding weed-free check, the highest net returns (4,691/ha), net benefit:cost ratio (0.43) were obtained under metribuzin 0.5 kg/ha pre-emergence.