Effect of duration and depth of burial on seed survival ofAvena fatua in arable soil

Seed survival ofAvena fatua L. var.fatua at various depths (0 to 50 cm) in a degraded chernozem was studied over a period of eight years. Statistical evaluation showed that seeds survived significantly during the first two years at depths of 0 to 20 cm, while at depths of 30 to 50 cm seeds statistically survived in the course of four years. After six years significant withering was observed within the whole soil profile, though 1% of seeds remained viable even until the eighth year. A tendency for prolonged survival of small seeds, and partly of medium ones, was observed in deeper soil layers in the sixth and seventh year.