Submitted to: Weed Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/19/2005
Publication Date: 12/17/2005
Citation: Davis, A.S., Cardina, J., Forcella, F., Johnson, G.A., Kegode, G., Lindquist, J., Luschei, E.C., Renner, K.A., Sprague, C.L., Williams, M. 2005. Environmental factors affecting seed persistence of 13 annual weeds across the U.S. corn belt. Weed Science. 53(6):860-868. Interpretive Summary: The main source of recurrent weed infestations in agricultural fields is from weed seeds mixed into the soil profile, also known as weed seedbanks. Both field studies and computer simulations indicate that reducing weed seedbank persistence will aid integrated weed management. To date, however, it has been difficult to make useful generalizations about the biology of weed seedbanks because most previous studies were performed at local scales with one or two weed species. In this study, we looked at seedbank persistence of 13 weed species over 9 locations in the North Central U.S. corn belt. We found that if we averaged results over locations we came up with very stable values for weed seedbank persistence. With benchmark values in place for weed seedbank persistence, it is now possible to set realistic goals for methods that reduce weed seedbank persistence.
Technical Abstract: Weed seedbanks have been studied intensively at local scales, but to date there have been no regional scale studies of weed seedbank persistence. Empirical and modeling studies indicate that reducing weed seedbank persistence can play an important role in integrated weed management. Annual seedbank persistence of 13 summer annual weed species was studied from 2001 through 2003 at nine locations in the North Central U.S. Effects of seed depth placement, tillage and abiotic environmental factors on seedbank persistence were examined through regression and multivariate ordinations. All species examined showed a negative relationship between hydrothermal time and seedbank persistence. Seedbank persistence was very similar between the two years of the study for common lambsquarters, giant foxtail and velvetleaf when data were pooled over year, location, depth and tillage. Seedbank persistence of common lambsquarters, giant foxtail and velvetleaf from October 2001 through 2002 and October 2002 through 2003 was, respectively, 52.3% and 60.0%, 21.3% and 21.8%, and 57.5% and 57.2%. These results demonstrate that robust estimates of seedbank persistence are possible when many observations are averaged over numerous locations. Future studies are needed to develop methods of reducing seedbank persistence, especially for weed species with particularly long-lived seeds.