GM crops do not increase yields, says new report
The Soil Association has published a report on the latest available research on GM crop yields over the last ten years. The yields of all major GM crop varieties in cultivation are lower than, or at best, equivalent to, yields from non-GM varieties.
Peter Melchett, Soil Association policy director, said:
"GM chemical companies constantly claim they have the answer to world
hunger while selling products which have never led to overall
increases in production, and which have sometimes decreased yields or
even led to crop failures. As oil becomes scarcer and more expensive,
we need to move away from oil dependent GM crops to producing food
sustainably, using renewable energy, as is the case with organic
farming."
Latest Research on GM Crop Yields
PRESS RELEASE 04/14/2008
GM crops as a whole
First generation genetic modifications address production conditions
(insect and weed control), and are in no way intended to increase the
intrinsic yield capacity of the plant.
* An April 2006 report from the United States Department of
Agriculture (USDA) states that “currently available GM crops do not
increase the yield potential of a hybrid variety. […] In fact, yield
may even decrease if the varieties used to carry the herbicide
tolerant or insect-resistant genes are not the highest yielding
cultivars”. (Fernandez-Cornejo, J. and Caswell, 2006)
* The United Nations Food and Agriculture Organization’s 2004
report on agricultural biotechnology acknowledges that GM crops can
have reduced yields (FAO, 2004). This is not surprising given that
first-generation genetic modifications address production conditions
(insect and weed control), and are not intended to increase the
intrinsic yield capacity of the plant.
* A 2003 report published in Science stated that “in the United
States and Argentina, average yield effects [of GM crops] are
negligible and in some cases even slightly negative”. (Qaim and
Zilberman, 2003). This was despite the authors being strong
supporters of GM crops.
* Yields of both GM and conventional varieties vary - sometimes
greatly - depending on growing conditions, such as degree of
infestation with insects or weeds, weather, region of production,
etc. (European Commission, 2000)
------------------------------------
Roundup Ready (RR) GM soya
Studies from 1999 - 2007 consistently show RR GM soya to yield 4 –
12% lower than conventional varieties.
* A 2007 study by Kansas State University agronomist Dr. Barney
Gordon suggests that Roundup Ready soya continues to suffer from a
yield drag: RR soya yielded 9% less than a close conventional relative.
* A carefully controlled study by University of Nebraska
agronomists found that RR soya varieties yielded 6% less than their
closest conventional relatives, and 11% less than high yielding
conventional lines (Elmore et al, 2001). This 6% ‘yield drag’ was
attributed to genetic modification, and corresponds to a substantial
loss in production of 202 kg/ha.
* In 1998 several universities carried out a study demonstrating
that, on average, RR soy varieties were 4% lower in yield than
conventional varieties (Oplinger et al., 1999). These results clearly
refuted Monsanto’s claim to the contrary (Gianessi, 2000).
* Yields of GM soybeans are especially low under drought
conditions. Due to pleiotropic effects (stems splitting under high
temperatures and water stress), GM soybeans suffer 25% higher losses
than conventional soybeans( Altieri and Pengue, 2005)
* 5 studies between 2001 -2007 show that glyphosate applied to
Roundup Ready soybeans inhibits the uptake of important nutrients
essential to plant health and performance. The resultant mineral
deficiencies have been implicated in various problems, from increased
disease susceptibility to inhibition of photosynthesis. Thus, the
same factors implicated in the GM soya yield drag may also be
responsible for increased susceptibility to disease. (Motavalli, et
al., 2004; Neumann et al., 2006; King, et al.,2001; Bernards,M.L,
2005; Gordon, B., 2007).
* The yield drag of RR soya is reflected in flat overall soybean
yields from 1995 to 2003, the very years in which GM soya adoption
went from nil to 81% of U.S. soybean acreage. By one estimate,
stagnating soybean yields in the U.S. cost soybean farmers $1.28
billion in lost revenues from1995 to 2003 (Ron Eliason, 2004).
* More recent evidence shows that the kilogram per hectare ratio
of soybean has been in decline since 2002, leading to the conclusion
that RR soy does not have an impact on yield (ABIOVE, 2006a).
--------------------------------------
Bt Maize
Only maize shows a persistent trend of yield increase into the
biotech era, but even here the rate of increase is no greater after
than before biotech varieties were introduced.
* A rigorous, independent study conducted in the U.S. under
controlled conditions demonstrated that Bt maize yields anywhere from
12% less to the same as near-isoline (highly similar) conventional
varieties (Ma & Subedi, 2005).
---------------------------------------
Bt Cotton
Despite claims of increased yield, Bt cotton has had no significant
impact in real terms.
* Average cotton yields have increased 5-fold since 1930, and
staged an impressive surge from1980 to the early 1990s. Cotton yields
then went flat, and continued to stagnate during the seven years of
GM cotton’s rise to dominance. The steep yield and production
increases in 2004 and 2005 were chiefly attributable to excellent
weather conditions (Meyer et al., 2007).
* Bt cotton, introduced to Australia in 1996, has not offered a
boost to the cotton sector, and since its adoption has not provided
improvements in either yield, or quality (ISAAA, 2006b).
* Cotton South Africa show constant yield levels before and
after adoption of Bt cotton (Witt et al 2005, cited in FoEI Who
Benefits 2007), in contradiction to ISAAA claims that Bt has brought
about a 24% yield increase in the region.
* Outbreaks of the secondary pests that are not killed by the Bt
insecticide have rendered Bt cotton ineffective in China (Connor, S.,
July 27, 2006), and are also becoming a problem in North Carolina
(Caldwell, D. 2002) and Georgia (Hollis, P.L., 2006).
* An article in Nature Biotechnology notes that the poor
performance of Bt cotton varieties used in India (which were
developed for the short U.S. growing season) is linked to the loss of
their insecticidal properties late in India’s longer growing season,
and because Bt cotton insecticide is not expressed in 25% of the
cotton bolls of India’s preferred hybrid cotton varieties (Jayaraman,
K.S., 2005)
---------------------------------------
During the Government's 2003 'national debate' on whether or not to allow commercial planting of GM crops, the Royal Institute of Chartered Surveyors, which represents land agents amongst others, predicted 'long-term chaos' and possible declines in land values if GM crops were planted. [1] Recent research in Sweden has confirmed that GM seeds can remain active in farmland for at least 10-years, adding scientific support to the RICS's concern about the impact on land values of growing GM crops.
Ends
For media enquiries please contact Clio Turton, Soil Association senior press officer, 0117 914 2448 / cturton@soilassociation.org
Notes to editor:
[1] Extract from an article published in Daily Telegraph: GM crop
trials 'pose threat to property prices'
By Charles Clover, Environment Editor (4 June 2003)
Property prices could be undermined if land is polluted with traces
of genetically modified crops, the Royal Institution of Chartered
Surveyors said yesterday at the start of a Government-sponsored
debate on whether Britain should approve commercial GM varieties.
Surveyors and land agents warned of "long-term chaos" in the property
market unless buyers were provided with information on the farms,
allotments and gardens where GM crops were or had been grown.
The RICS said accurate information on where GM crops were planted was
essential to buyers wishing to purchase or rent land for non-GM or
organic production and to financial institutions lending against land
and property.
References:
ABIOVE, 2006a. Sustainaibility in the Legal Amazon. Presentation by
Carlo Lovatelli at the Second Roundtable on Responsible Soy.
Paraguay, 1 September 2006. http://www.abiove.com.br/english/
palestras/abiove_pal_sustent_amazonialegal_us.pdf
Altieri, M., Pengue, W., 2005. GM Soya Disaster in Latin America: Hunger, Deforestation and Socio-ecological Devastation.
Bernards, M.L. et al, 2005. Glyphosate interaction with manganese in tank mixtures and its effect on glyphosate absorption and translocation. Weed Science 53: 787-794.
Caldwell, D. 2002. A Cotton Conundrum. Perspectives OnLine: The
Magazine of the
College of Agriculture and Life Sciences, North Carolina State
University,Winter 2002. http://www.cals.ncsu.edu/agcomm/magazine/
winter02/cotton.htm
Connor, S., July 27, 2006. Farmers use as much pesticide with GM
crops, US study finds. The Independent.
http://news.independent.co.uk/environment/article1199339.ece
Elmore et al, 2001. Glyphosate-Resistant Soybean Cultivar Yields
Compared with Sister Lines, Agron J 2001 93: 408-412, quote from the
University of Nebraska press release online at http://
ianrnews.unl.edu/static/0005161.shtml
European Commission, 2000. Economic Impacts of Genetically Modified
Crops on theAgri-food Sector. http://europa.eu.int/comm/agriculture/
publi/gmo/cover.htm
FAO, 2004. The State of World Food and Agriculture 2004.
Biotechnology: Meeting the Needs of the Poor? http://www.fao.org/
newsroom/en/focus/2004/41655/
Fernandez-Cornejo, J. & Caswell. April 2006. Genetically Engineered
Crops in the UnitedStates. USDA/ERS Economic Information Bulletin n. 11.
http://www.ers.usda.gov/publications/eib11/eib11.pdf
FoEI, January 2007. Who Benefits from GM crops? An analysis of the global performance of GM crops (1996-2006)
Gianessi, L.P., April 2000. Agriculture Biotechnology: Benefits of
Transgenic Soybeans. National Center for Food and Agricultural
Policy, p. 63.
http://www.ncfap.org/reports/biotech/rrsoybeanbenefits.pdf
Gordon, B., 2007. Manganese nutrition of glyphosate-resistant and
conventional
soybeans. Better Crops, Vol. 91, No. 4: 12-13
Hollis, P.L., February 15 2006. Why plant cotton’s new genetics?
Southeast Farm Press. http://southeastfarmpress.com/mag/
farming_why_plant_cottons/
ISAAA, 2006b. GM crops: the first ten years- Global Socio-Economic
and Environmental impacts. http://www.isaaa.org/resources/
publications/briefs/36/download/isaaa-brief-
36-2006.pdf
Jayaraman, K.S., November 2005. Monsanto’s Bollgard potentially
compromised in
India. Nature Biotechnology.
King, A.C., L.C. Purcell and E.D. Vories, 2001. Plant growth and nitrogenase activity of glyphosate-tolerant soybean in response to foliar glyphosate applications. Agronomy Journal 93:179-186.
Ma & Subedi, 2005. "Development, yield, grain moisture and nitrogen
uptake of Bt corn hybrids and their conventional near-isolines,"
Field Crops Research 93 (2-3): 199-211, at http://
www.sciencedirect.com/science?
_ob=ArticleURL&_udi=B6T6M4DRBBYB1&_user=10&_coverDate=09%2F14%
2F2005&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_versi
on=1&_urlVersion=0&_userid=10&m5=5299e6ebd64c6b4db4566ee6f44eced2
Meyer, L., S.MacDonald& L. Foreman,March 2007. Cotton Backgrounder. USDA Economic Research Service Outlook Report.
Motavalli, P.P. et al., 2004. “Impact of genetically modified crops and their management on soil microbially mediated plant nutrient transformations,” J. Environ. Qual. 33:816-824;
Neumann, G. et al., 2006. “Relevance of glyphosate transfer to non-
target plants via the rhizosphere,” Journal of Plant Diseases and
Protection 20:963-969.
Oplinger, E.S et al., 1999. Performance of Transgenetic Soyabeans,
Northern US.
http://www.biotech-info.net/soybean_performance.pdf
Qaim, M. and Zilberman, D., 7 February 2003. “Yield Effects of
Genetically Modified
Crops in Developing Countries” in Science, vol. 299, p. 900.
Ron Eliason, 2004. Stagnating National Bean Yields. 2004 Midwest Soybean
Conference, cited by Dan Sullivan, “Is Monsanto’s patented Roundup
Ready gene
responsible for a flattening of U.S. soybean yields,”NewFarm.org,
September 28, 2004, online at http://www.newfarm.org/features/0904/soybeans/index.shtml