Control of Invasive Plants by the Phytotoxicity Effect of Sorghum bicolor [L.] Moench

Owing to an increasing demand for food, a constant agricultural production flow must be maintained. Further, for doing so, the use of pesticides is necessary. An alternative that results in less damage to the ecosystem and people themselves may be identified by studies on the allelopathic effect of weeds. Therefore, this work aimed to evaluate the allelopathic action of hexane, dichloromethane, butanol, and ethyl acetate fractions of sorghum (Sorghum bicolor [L.] Moench) on the initial growth of morning glory (Ipomoea grandifolia [Dammer] O’Donell) and slim amaranth (Amaranthus hybridus L.), which was verified by the percentage of germination, speed of germination, seedling length, and fresh and dry biomass weight. The experiments were conducted in an incubation chamber at 25 °C for 7 and 14 days for morning glory and slim amaranth, respectively. The experimental design was completely randomized, with five replicates in Petri dishes. The data were evaluated by analysis of variance, and the averages between each treatment were compared using the Scott Knott test at a 5% significance level. The results indicated that the dichloromethane and ethyl acetate fractions decreased the initial growth of morning glory and slim amaranth more, when compared with the effects of hexane and butanol.