2,4-D residual activity over soybean emergence in soils with distinct textures

Abstract

– This research aimed to evaluate the 2.4-D residual activity over soybean emergence in soils with distinct textures. The experiments, each one with a distinct soil type (clay sand and clay), were conducted in greenhouse conditions, in a randomized entirely design, in factorial scheme 6x2+1 with treatments constituted by the combination of six application period: 0, 3, 5, 7, 10 and 14 days before soybean sown (DBS) and two 2.4-D (502.5 e 1,005 g e.a. ha-1) doses, besides an absolute check without herbicide application. 2.4-D residual activity was evaluated through the emergence speed index (ESI), germination percentage (%), visual phytointoxication (%), plant high (cm) and soybean plants dry biomass (g) at 26 DBS. In both soil types, 2.4-D residual activity was observed, ranging in function of herbicide dose and time period between herbicide application and soybean sown. The effect was more pronounced in plants grown on cland soil where there was higher phytointoxication and reduction of dry biomass in relation to the check, mainly at the treatment where herbicide was sprayed and soybean genotype V-Max sowed in following.