Effect of herbicides applied against of weeds in soybean (Glycine max L.) field

Herbicides, if used properly, are safe and effective in controlling weeds in soybean. The choice of herbicide, however, depends on the predominant weed species and the availability of the herbicide. In soybean field distributed 21 species of weedsof 20 genus belonging to 14 families, that are the determined 71.5% annual, 9.5% biennialweeds and 19.0% perennial weeds. Herbicides are available for pre-emergence or post emergence weed control in soybean. For examining testable variations, 278 weeds in 1m2 area were counted awet weight 1000 g, a dry weight 138.1 referring to weed density at the highestdoses 1.5-2.0 L of Targonherbicide applied in variations, whereas 92 weeds in 1m2 area were counted a wet weight 575 g, a dry weight 120.1 were to rubbish most lesser Gallant superherbicide doses at 0.45-0.65 L/ha applied in variations. In soybean field for controlling to weeds were applied Targon herbicide at doses 1.0-2.0l/ha , whereas weed species density reduced by 91.4-93.2% and the weight by 47.2-59.7%, Gallant super herbicide at doses 0.45-0.65 l/ha,the weed species density reduced by 91.1-96.3, and the weight by 37.3-58.9%, Cobra herbicide at doses 0.45-0.55 l/ha that weed species density reduced by 90.2- 95.0% and the weight by 36.7-41.4%, Flex herbicide at doses 1.65-1.85 l/ha that weed species density reduced by 95.6-94.6% and the weight by 31.2-32.5 percent respectively. The effect of chemical weed control with reduced herbicide doses on the weed population density in soybean yield was observed. Weed competition has reduced an important morpho-physiological trait in soybean. DOI: http://dx.doi.org/10.5564/mjas.v11i2.218 Mongolian Journal of Agricultural Sciences Vol.11(2) 2013 pp.59-62