Seed longevity and dormancy of four summer annual grass weeds in turf

Digitaria sanguinalis, Eleusine indica, Setaria glauca and S. viridis are troublesome summer annual weeds in turf. For taking rational decisions on the necessity for the level and type of weed management, it is important to know when weeds are ready to emerge (dormancy status) and also how long weed seeds can survive in the soil. Seeds of these four species were buried 4.0-4.5 cm deep in steel mesh net bags placed under permanent turf and periodically exhumed for 3 years to evaluate viability and determine the dormancy/non-dormancy cycle. D. sanguinalis, S. glauca and S. viridis showed the typical dormancy cycle of summer annual species, and their seed viability declined completely after 3 years of burial. In contrast, E. indica demonstrated unusual behaviour, with long persistence and no dormancy.