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Record information and status
Record ID
Date of creation
2008-04-25 16:30 UTC (andrew.bowers@cbd.int)
Date of last update
2012-05-08 19:52 UTC (dina.abdelhakim@cbd.int)
Date of publication
2012-05-08 19:52 UTC (dina.abdelhakim@cbd.int)

General Information
Weeds in fields with contrasting conventional and genetically modified herbicide-tolerant crops. I. Effects on abundance and diversity
M. S. Heard, C. Hawes, G. T. Champion, S. J. Clark, L. G. Firbank, A. J. Haughton, A.M. Parish, J. N. Perry, P. Rothery, R. J. Scott, M. P. Skellern, G. R. Squire and M. O. Hill
Organization(s) involved in the publication of this resource
Dr. Matt Heard
Centre for Ecology & Hydrology
Natural Environment Research Council (NERC)
Monks Wood
Abbots Ripton
Huntingdon, Cambridgeshire
United Kingdom of Great Britain and Northern Ireland, PE282LS
Phone:+1487 772400
Fax:+1487 773467
Url:NERC Centre for Ecology and Hydrology
  • English
Publication date
Summary, abstract or table of contents
We compared the seedbanks, seed rains, plant densities and biomasses of weeds under two contrasting systems of management in beet, maize and spring oilseed rape. Weed seedbank and plant density were measured at the same locations in two subsequent seasons. About 60 fields were sown with each crop. Each field was split, one half being sown with a conventional variety managed according to the farmer's normal practice, the other half being sown with a genetically modified herbicide-tolerant (GMHT) variety, with weeds controlled by a broad-spectrum herbicide. In beet and rape, plant densities shortly after sowing were higher in the GMHT treatment. Following weed control in conventional beet, plant densities were approximately one-fifth of those in GMHT beet. In both beet and rape, this effect was reversed after the first application of broad-spectrum herbicide, so that late-season plant densities were lower in the GMHT treatments. Biomass and seed rain in GMHT crops were between one-third and one-sixth of those in conventional treatments. The effects of differing weed-seed returns in these two crops persisted in the seedbank: densities following the GMHT treatment were about 20% lower than those following the conventional treatment. The effect of growing maize was quite different. Weed density was higher throughout
the season in the GMHT treatment. Late-season biomass was 82% higher and seed rain was 87% higher than in the conventional treatment. The difference was not subsequently detectable in the seedbank because the total seed return was low after both treatments. In all three crops, weed diversity was little affected by the treatment, except for transient effects immediately following herbicide application.
Thematic areas
Background material to the “Guidance on risk assessment of living modified organisms”
Is this document is recommend as background material for the “Guidance on Risk Assessment of Living Modified Organisms”
Section(s) of the “Guidance on Risk Assessment of Living Modified Organisms” this background material is relevant
Additional Information
Type of resource
  • Article (journal / magazine / newspaper)
DOI 10.1098/rstb.2003.1402
Publisher and its location
The Royal Society, London
© 2003 The Royal Society
14 page journal article
Philosophical Transactions of The Royal Society B (Biological Sciences)
Keywords and any other relevant information
arable weeds; Britain; genetically modified herbicide-tolerant crops; Farm Scale Evaluations

Phil. Trans. R. Soc. Lond. B (2003) 358, 1819-1832
LMO categories: Plants