The seedbank dynamics of feral rye (Secale cereale)

Buried feral rye seeds were rapidly depleted in soil in the first year due to in situ germination. Less than 1% of the viable seeds persisted after 45 mo of burial. Although after 5 yr, a small number of seedlings still emerg ed, soil seedbank decline was rapid when seed production was prevented. A l ow level of induced dormancy was detected and may explain the small populat ions of feral rye that persisted. Seed and seedling population shifts were large over a 5-yr period and were related to environmental conditions. Till age or chemical control of feral rye in the fallow period reduced populatio ns compared to the untreated weedy check. Moldboard plowing provided the gr eatest feral rye control compared to shallow tillage and chemical fallow. F eral rye seedbank populations rebounded following a wet final year of the s tudy. These results help explain feral rye persistence in a wheat-fallow ag roecosystem by the persistence of a small portion of the seedbank and by la rge seed inputs into the system during environmentally favorable years. Fer al rye reduced wheat yield as much as 92% and represented up to 73% contami nation in harvested wheat.