Survival and distribution of weedy rice seedbank after twenty-two years of different rice cropping systems

ABSTRACT: Weedy rice (Oryza sativa L.) is the most problematic weed in fields due to few control management alternatives it, because of genetic similarity with crop. Different cropping systems (regarding soil preparation before sowing) have been used as options persistence and emergence seedbank. Therefore, objective this study was evaluate longevity vertical distribution weedy seeds seedbank after 22 years different systems. Data analyzed a two-way factorial, carried out for [no-tillage (NT), conventional tillage (CT), wet direct-seeded (WDS)] one factor sampling depth (0-2, 2-5, 5-10 10-20 cm) other factor. The number whole deteriorated per m-2 were assessed, well viability (%). No effect between detected up 5 cm, however at cm CT WDS showed higher amount seeds, cm. As increased, NT fewer while less reduction observed WDS. spread viable profile from 0 20 depth. After there are 10 three no difference among them depth, demonstrating serious problem species.