Longevity of Barnyardgrass, Green Foxtail, and Yellow Foxtail Seeds in Soil

Seeds of barnyardgrass [Echinochloa crus-galli (L.) Beauv.], green foxtail [Setaria viridis (L.) Beauv.], and yellow foxtail [Setaria lutescens (Weigel) Hubb.] were buried 2.5, 10, and 20 cm deep in irrigated and nonirrigated sandy loam. Samples were exhumed periodically for 15 yr to determine viability. Viability declined with time. Three percent or less of the seeds of each species remained viable 13 yr after burial, and none were viable after 15 yr. Survival of seeds under apparently uniform conditions varied extremely. Thus, subtle differences in environmental conditions profoundly affect longevity of seeds.