Effect of herbicides on plant growth and seed yield and quality of soybean (Glycine max L. Merr.)

Abstract

Weeds create a great problem for soybean production and to overcome this problem a large number of weedicides are being applied prevalently worldwide. Gradually increasing the use of chemical herbicides, not only creating resistance against these chemicals among the weeds and polluting the environment, but also influencing the main crop and deteriorating the produce quality. To focus this problem a two-year experiment was laid down during ‘kharif’, at Norman E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, to evaluate the detrimental effect of herbicides on soybean plant growth and seed quality. The study come up with the results that the growth parameters during 60-90 DAS (days after sowing) viz., crop growth rate (CGR 0.235 g/day), relative growth rate (RGR 0.014 g/ g/ day) and net assimilation rate (NAR 2.250 g/cm2/day) decreased due to higher weed competition in weedy plot. Weed competition also significantly reduced yield parameters like number of branches (3.8) and pod per plant (25.4), seed per pod (2.4), seed yield (386 kg/ ha), seed index (11.8 %), and straw yield (1611 kg/ha). The highest seed yield (2665 kg/ha) was recorded with application of diclosulam (as pre-emergence) followed by one hand weeding, which was statistically equal with the treatment in which diclosulam followed by haloxyfop (as post-emergence) was applied. These herbicides also significantly alter the fatty acid composition of soybean seed oil.