Field experiments were conducted to quantify cumulative and annual rates of woolly cupgrass seedling emergence and seed mortality and to characterize woolly cupgrass seedling emergence patterns. Woolly cupgrass seed bank decline was rapid, declining by an average of 73, 96, and 99.5% after 1, 2, and 3 yr, respectively. Woolly cupgrass seed mortality accounted for a much greater portion of seed loss from the seed bank (80%) than germination and emergence (19.5%) during the 3-yr period. Annual rates of emergence ranged from 3 to 17% of the fall seed bank and were similar between seed banks established in different years when compared within the same year. Annual rates of mortality ranged from 50 to 92% and varied between seed banks established in different years when compared within the same year; older seed banks had higher rates of mortality than younger seed banks. For first-year seed banks, 97 to 99% of the total season emergence occurred within the first 3 wk of emergence. However, for second- and third-year seed banks, a greater percentage of the total season emergence occurred later in the season compared with emergence that occurred during the first year. The data suggest that in addition to various environmental and seed-source factors, seed bank age may also play a role in seed mortality rate and seedling emergence pattern.
Nomenclature: Woolly cupgrass, Eriochloa villosa (Thunb.) Kunth ERBVI.