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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #231956
Title: Seedbank and emerged weed communities following adoption of glyphosate-resistant crops in a long-term tillage and rotation study.

Author
item SOSNOSKIE, L - UNIV OF GA
item HERMS, C - OHIO STATE UNIV
item CARDINA, J - OHIO STATE UNIV
item Webster, Theodore

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2009
Publication Date: 5/1/2009
Citation: Sosnoskie, L.M., Herms, C.P., Cardina, J., Webster, T.M. 2009. Seedbank and emerged weed communities following adoption of glyphosate-resistant crops in a long-term tillage and rotation study. Weed Science. 57(3):261-270.

Interpretive Summary: The abundance and composition of species in arable weed seedbanks and aboveground weed communities reflect past and current management of soils, crops, and weeds. Weed species density and diversity can be affected by tillage, crop rotation, crop and weed management, and local environmental conditions. The principal species flourishing under intense tillage can differ from those dominating systems with little or no soil disturbance. The commercial release and widespread adoption of genetically-modified glyphosate-tolerant crops has transformed a significant proportion of the agricultural landscape. There is concern that the widespread use of a single herbicide mode-of-action across space and time will significantly alter agricultural weed community dynamics in crop fields. The compositions of the germinable weed-seedbank and aboveground weed communities in a long term tillage and rotation study were characterized four to six years after the adoption of glyphosate tolerant corn and soybeans. Adoption of glyphosate-tolerant crops did not affect trends observed in density, diversity, community composition and species associations, suggesting that the switch to a POST applied glyphosate protocol did not significantly alter the weed seedbank communities in the short term.

Technical Abstract: The compositions of the germinable weed-seedbank and aboveground weed communities in a long term tillage and rotation study were characterized four to six years after the adoption of glyphosate tolerant corn and soybeans. Averaged across rotations, mean germinable weed seed density and diversity were greatest in no-tillage (NT) as compared to the minimum-tillage (MT) and conventional-tillage (CT). Averaged over years and tillage environments, density and diversity were greater in the corn-oat-hay rotation compared to continuous corn and corn-soybean rotations. Similar trends in density and diversity were observed for the emerged weed communities. Weed seed bank in corn-oat-hay rotational system differed from continuous corn and corn-soybean. Weed seedbank in NT differed from MT and CT. The number of significant indicator species for the seedbank and weed communities was generally greater in the three-crop rotation as compared to the continuous corn and corn-soybean rotations for all three years. The trends observed in density, diversity, community composition and species associations with particular treatments after the adoption of glyphosate-tolerant corn and soybeans, were also observed when soil applied herbicides were the primary components of the weed management program in the study. This suggests that the switch to a POST applied glyphosate protocol did not significantly alter the weed seedbank communities in the short term.