Interference of glyphosate-resistant sourgrass regrowth density on soybean development and yield

Abstract

Sourgrass is a prevalent weed species in various agricultural systems and poses a persistent challenge in soybean crops due to its glyphosate resistance, high aggressiveness, and strong establishment capacity in no-tillage systems. However, studies investigating the interference of sourgrass regrowth in soybean cultivation remain limited. Thus, the objective of this study was to assess the impact of increasing densities of glyphosate-resistant sourgrass regrowth on the development and yield of ‘TMG-7067’ soybean. The experiment was conducted in a randomized complete block design with seven treatments and four replications. Treatments were arranged in a factorial arrangement, with factors being the duration of coexistence (49, 61, 90, and 117 days) and sourgrass densities (0, 1, 2, 3, 4, 5, and 6 plants m⁻²). The evaluated parameters included plant height, stem diameter, leaf area, first pod insertion height, number of pods, dry matter, and grain yield. Soybean exhibited significant yield losses in all treatments with sourgrass presence, exceeding 40% compared to the control. Densities of one or more sourgrass regrowth plants m⁻² resulted in maximum interference in soybean development and yield.