Long-term seed survival of common ragweed (Ambrosia artemisiifolia L.) after burial

Ambrosia artemisiifolia is a serious threat to human health and agricultural yield. Due to its annual growth form management should focus on the prevention of seed production in the long run. The long-term survival of ragweed seeds depends on the implementation of viable seeds to the persistent soil seed bank. In a field study, we tried to find out how long this species must be surveyed/managed to reach the goal of complete eradication after burial of seeds into mineral soil. We tested for the influence of different seed sources (origin), different soil depths of burial, different experimental sites in Middle Europe (labs), and duration of burial on the viability of seeds by germination test plus TTC-test. In our study, seed origin had a highly significant influence on the seed survival. In all the 10 years of the experiment, seeds sampled from a rural stand in Austria showed significantly lower viability rates than seeds from Hungary. The Hungarian seeds from arable fields had viability rates of up to 90% even after 10 years’ burial. Burial depth (7 cm/25 cm) had no significant influence on the viability rates but we detected a serious influence of the experimental sites which can be caused either by the burial site conditions (differences in soil and climate) or by different implementation of the manuals for germination tests and colouration test using 2,3,5-triphenyltetrazolium chloride. The decline of viability within the 10-year period differed by seed origin, but was generally faster in the first few years but relatively low in the following years. Due to the fact that we found 30 to 90% viable seeds after 10 years burial there is substantial evidence that soil perturbation (digging animals, ploughing) should be avoided for even more than ten years in habitats that are highly infested with ragweed.