Sources of viable seed loss in buried dormant and non-dormant populations of wild oat (Avena fatua L.) seed in Colorado

Buried populations of dormant and non-dormant wild oat (Avena fatua) seed persisted less than 2 years, depth of burial having very little influence on their survival. The mode of seed disappearence, however, was closely related to their depth in the soil. Seed exhaustion through germination in situ increased with increasing depth in the soil, whereas exhaustion through non-viability increased with decreasing depth. Physical and induced dormancies are apparently not capable of supporting prolonged persistence of A. fatua seeds in soil. The lack of prolonged persistence of A. fatua seeds in Colorado derives from a lack of genetically programmed embryonic dormancy in these populations and makes A. fatua easier to control in Colorado than in other cereal-growing regions south of the 43rd parallel because it dramatically reduces the survival of seeds in the soil. The most effective non-chemical control of this grass weed is achieved by means of the shallowest cultivations possible, carried out as late as possible.