Boosting productivity and profitability of soybean (Glycine max) in Uttarakhand by weed management through herbicides and mulch

A field experiment was conducted during the rainy (kharif) season of 2015 at Pantnagar, Uttarakhand, to assess the effect of 3 herbicides, viz. pendimethalin, imazethapyr and sulfentrazone and wheat (Triticum aestivum L.) straw mulch on weed dynamics, yield and economics of soybean [Glycine max (L.) Merr.]. Unchecked weed growth caused 55% reduction in seed yield of soybean. Pendimethalin @ 1.0 kg/ha followed by (fb) imazethapyr @ 0.1 kg/ha + mulch @ 5 t/ha at 25 days after sowing (DAS) being at par with mulch @ 5 t/ha after the first weeding and mulch @ 5 t/ha fb sulfentrazone @ 0.3 kg/ha recorded significantly lower weed density and weed dry weight and therefore higher weed-control efficiency at harvesting. The highest seed yield (2.79 t/ha) was obtained under weed-free check, which was at par with pendimethalin @1.0 kg/ha fb imazethapyr @ 0.1 kg/ha + mulch @ 5 t/ha at 25 DAS (2.60 t/ha), mulch @ 5 t/ha after the first weeding (2.59 t/ha) and mulch @ 5 t/ha fb sulfentrazone @ 0.3 kg/ha (2.51 t/ha). The highest benefit: cost ratio was recorded under pre-emergence application of pendimethalin @1.0 kg/ha fb post-emergence application of sulfentrazone @ 0.3 kg/ha (2.93), which was at par with mulching of wheat straw @ 5 t/ha fb sulfentrazone @ 0.3 kg/ha (PoE) (2.82). The new herbicide sulfentrazone provided satisfactory control of all types of weed flora.