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Weed interference with field‐grown soyabean decreases under elevated [CO 2 ] in a FACE experiment

2012; Wiley; Volume: 52; Issue: 3 Linguagem: Inglês

10.1111/j.1365-3180.2012.00915.x

1365-3180

Adam S. Davis, Elizabeth A. Ainsworth,

Plant Parasitism and Resistance

D avis AS & A insworth EA (2012). Weed interference with field‐grown soyabean decreases under elevated [CO 2 ] in a FACE experiment. Weed Research 52 , 277–285. Summary Rising atmospheric [CO 2 ] is predicted to affect C 3 and C 4 weed interference with crop species differently, with C 3 weeds benefiting more from elevated [CO 2 ] (eCO 2 ) than C 4 species. Our aim was to quantify impacts of eCO 2 on C 3 and C 4 weeds at three levels of biological organisation: individual, population and community. We conducted a field study in 2007 and 2008 within the SoyFACE experiment in Champaign, Illinois, USA, in which Amaranthus rudis (C 4 ) and Chenopodium album (C 3 ) were grown with soyabean. This is a Free Air CO 2 Enrichment (FACE) experiment. Elevated [CO 2 ] influenced weeds at all levels of biological organisation. However, community‐level impacts were largest. Interference by A. rudis and C. album with soyabean was 37% and 11% lower, respectively, in eCO 2 . In residual weed communities under ambient [CO 2 ] (aCO 2 ), C 3 and C 4 species were equally likely to dominate the community, whereas in eCO 2 , there was a 90% chance of community dominance by C 3 species. Future investigations of weed ecology and global change under FACE conditions may improve their inference space by including sources of environmental stress such as ozone, heat and drought.