Persistence of seeds of some grass species in cultivated soil

Freshly collected ripe caryopses of twenty‐five indigenous grasses were mixed with the top 7–5 cm of sterilized soil confined in cylinders sunk in the ground and cultivated three times yearly. There was a flush of seedlings of most species shortly after sowing, but species differed in the persistence of viable seeds. About one third, including Bromus sterilis, B. hordeaceus, Lolium perenne ssp. perenne, Arrhenatherum elatius and Alopecurus pratensis , produced few seedlings after the initial flush. Others such as Deschampsia cespitosa, Holcus lanatus and Poa trivialis , recognized as forming persistent seed banks in grassland soils, produced appreciable numbers of seedlings in the second year after sowing. Most persistent were species that occur as arable weeds ( Avena fatua, Poa annua ) or in wetlands ( Glyceria plicata, G. maxima, Alopecurus geniculatus ). Emergence from the seed bank generally followed soil disturbance but some species ( Aira praecox, Avena fatua, A. sterilis ssp. ludoviciana, Danthonia decumbens ) exhibited consistent seasonal patterns which may be associated with cyclic changes in germination requirements of the buried seeds.