Weed interference capacity on soybean yield

Abstract

Among biological factors, weeds are the most important limiting factor for crop yields, as well as increasing production costs. The aim was to determine the influence of control and coexistence of weed community on soybean crop yield and to define the period before interference, the critical period of interference prevention and the total period of interference prevention, with the comparative use of chemical and mechanical methods for weed eradication. The study was conducted in an experimental field in the 2018/2019 harvest. A randomized block with four replications was implemented as experimental design, using two methods for control. The evaluated periods were 0-10, 0-20, 0-30, 0-40, 0-50, 0-60 and 130 days after crop emergence. It was possible to observe that the use of the chemical method generated a higher yield compared to mechanical method. The period before the interference in both chemical and mechanical management was similar, approaching 20 days after crop emergence. The critical period of interference prevention was between 20-50 and 40.5 days after crop emergence in chemical and mechanical methods, respectively. The total period of interference prevention was extended to 50 and 40.5 days after crop emergence in chemical and mechanical methods, respectively. The reduction in productivity due to weed interference was 1639 kg ha-1 (55%)and 947 kg ha-1 (34.6%) in chemical and mechanical methods, respectively.

Weed Competition on Soybean Varieties from Different Relative Maturity Groups

“…Thus, the damage caused by weed competition in the soybean crop may vary according to the variety and the relative maturity group. The technical-scientific literature shows different results regarding the critical period of interference prevention in the soybean crop [12][13][14]. Considering the wide variation in terms of the cycle extension of soybean varieties available for cultivation, it is hypothesized that they may have a distinct competitive potential with weeds, as well as different levels of sensitivity to the interference imposed by the weed community [5,6,10].…”

Shortening critical period of weed control at soybean by residual herbicide mixtures

“…Weed interference is accentuated in the beginning of the cycle and will generally end with crop canopy closure. The "window" between these periods is defined as the critical period for weed control -CPWC (Rüdell et al, 2021;Knezevic et al, 2002), a period calculated by days, years or stage of growth, where the adoption of control methods is recommended (Tursun et al, 2016).…”