Phytosociology and cover analysis in the suppression of weeds from an Amazonian agrosystem

Weeds can occur in cultivated areas, competing with crops and causing considerable losses. Herbicides are the basis of weed control; however, they are questionable due to their possible negative impacts on human health and the environment. An alternative for controlling weeds is using cover plants. This study aimed to determine the floristic composition of weeds in an Amazonian agrosystem with cover plants and to evaluate the production of biomass, the soil cover rate and the weed suppression potential of cover plants. The experimental design was in randomized blocks, in a 4 x 2 factorial scheme. The factors under study were the cover species ( Brachiaria ruziziensis , Canavalia ensiformis , Mucuna deeringiana ) and the control group that consisted of weeds, evaluated during two agricultural years (2017 and 2018), with four replicates. Digitaria horizontalis was the most important weed species and was completely suppressed by B. ruziziensis . This cover type had a large production of biomass, greater coverage of the soil and high suppression of weeds in the Amazonian agrosystem.