Soil solutions were extracted from a pasture area, formed with Brachiaria brizantha cv. Marandu for over 5 years, to evaluate the allelopathic effects of this pasture grass on seed germination, dormancy, mortality, percentage of normal plants, germination velocity and shoot growth of B. brizantha cv. Marandu and Panicum maximum cv. Tanzânia and pasture weeds Sida rhombifolia and Peschiera fuchsiaefolia. The germination substrate was humidified with 12 mL of the following treatments: Soil solution from an area cultivated with B. brizantha; soil solution from an area without B. brizantha (Forest); distilled water and Polyethylene glycol solution (molecular weight = 6000), combined with solutions from soil with and without B. brizantha. Allelopathic effects occurred at germination velocity index for P. maximum Tanzânia. For shoot growth, both pasture and forest soil solutions had a negative effect on root growth of S. rhombifolia. No effects were observed for P. fuchsiaefolia.
allelopathy; weeds; seeds
