Abstract Background The presence of straw on the soil contributes to the management of weeds in several production systems and this understanding needs to be extended to annual crops under no-tillage systems. Objective This study aimed to evaluate the effect of covering the soil with 5 Mg ha-1 of maize straw on the germination and growth of Digitaria insularis, Conyza spp., Bidens pilosa, Amaranthus hybridus, Euphorbia heterophylla, and Eleusine indica. Methods For this purpose, completely randomized design was used with sixteen and third two replicates. Four assays were conducted between the years 2019 and 2020 in a greenhouse. The number of emerged seedlings was evaluated at 7, 14, and 21 days after sowing (DAS) and the shoot dry weight of the seedlings and the correlation between these variables were evaluated at 21 DAS. Results The covering of the soil with straw decreased the weed infestation of all species, except E. heterophylla, which presented positive correlation for the variables evaluated, denoting that the straw had no effect on the germination and growth of this species. The variables evaluated showed no correlation for the other species, denoting that the soil cover with straw suppress the germination and growth of plants. Conclusions We conclude that soil cover with 5 Mg ha-1 of maize straw is a tool for the control of weeds of the species evaluated, except E. heterophylla, and an option for integrated weed managements that can complement the residual effect of herbicides.

ABSTRACT The use of pre-emergent herbicides is important for the current agricultural production systems that present weeds resistant to herbicides. Considering the complexity of using these products, the objective of this work was to evaluate their selectivity and residual weed control in soybean crops and their effect on the weeds Amaranthus hybridus, Bidens pilosa, Digitaria insularis, Eleusine indica, and Euphorbia heterophylla. The herbicide selectivity experiments were conducted under field conditions in the 2017/18 and 2019/20 crop seasons and the herbicide efficacy experiments were conducted under greenhouse conditions. The herbicides s-metolachlor and flumioxazin can be applied on day of the soybean sowing without causing significant grain yield losses. Diclosulam and sulfentrazone are safe for soybean crops when applied at least 14 days before sowing. The herbicides used proved to be good options for weed management systems for soybean crops; flumioxazin and sulfentrazone were the herbicides that promoted the best control for all evaluated weed species and ensured a residual effect of at least 30 days.