Altieri 2005 the Myth of Coexistence GMO and Agroecology

10.1177/0270467605277291ARTICLEBULLETIN OF SCIENCE, TECHNOLOGY & SOCIETY / August 2005Altieri / MYTH OF COEXISTENCE

The Myth of Coexistence:Why Transgenic Crops Are Not Compatible WithAgroecologically Based Systems of ProductionMiguel A. AltieriUniversity of California, Berkeley

The coexistence of genetically modified (GM) cropsand non-GM crops is a myth because the movement oftransgenes beyond their intended destinations is a cer-tainty, and this leads to genetic contamination of or-ganic farms and other systems. It is unlikely thattransgenes can be retracted once they have escaped,thus the damage to the purity of non-GM seeds is per-manent. The dominant GM crops have the potential toreduce biodiversity further by increasing agriculturalintensification. There are also potential risks tobiodiversity arising from gene flow and toxicity tonontarget organisms from herbicide-resistant (HT)and insect-resistant (Bt) crops. Unless whole regionsare declared GM agriculture free, the development ofdistinct systems of agriculture (GM and non-GM) willbe impossible as GM agriculture emerges at theexpense of all other forms of production.

Keywords: agroecology; coexistence; transgeniccrops; ecological impacts; organic farmingCoexistence in agriculture refers to a state where dif-ferent primary production systems such as organicproduction, conventional agriculture, and geneticallymodified (GM) systems occur simultaneously or adja-cent to one another, while each contributing in theirown way to the overall benefit of a region or country,ensuring that their operations are managed so that theyaffect each other as little as possible. Many argue thatthis concept is not new as in many countries theorganic production sector that usually comprises a rel-atively small group of farmers has for years been ableto produce alongside conventional farmers who useproducts and methods forbidden in organic production(Byrne & Fromherz, 2003). This is of course not the

case when one considers spray drift or pesticide resi-dues originating in conventional systems and thatadversely affect neighboring organic systems. Driftoccurs unavoidably with all ground and aerial meth-ods of pesticide application. In fact, 10% to 35% of thepesticide applied with ground application equipmentmisses the target area; with aircraft, 50% to 75% of thepesticide applied misses the target area. Clearly driftdamage, human exposure, and widespread contamina-tion are inherent in the process of pesticide applicationand expose the fact that conventional agriculture is notcompatible with organic farming. Data on crop lossesand environmental costs due to chemical drift are diffi-cult to obtain, however Pimentel and Lehman (1993)estimated U.S. crop losses due to the use of pesticidesto reach about $950 million. These costs do notinclude those derived from outbreaks of several peststriggered in whole regions due to development ofpesticide resistance by pests and destruction ofpopulations of natural enemies.

A similar case occurred with the Green Revolutionin the developing world. The imposition of a Westernmodel of agricultural development did not coexistwith the indigenous systems of production because itassumed that progress and achieving development intraditional agriculture inevitably required the replace-ment of local crop varieties for improved ones and thatthe economic and technological integration of tradi-tional farming systems into the global system was apositive step that enabled increased production, in-come, and common well-being (Tripp, 1996). But asevinced by the Green Revolution, the introduction ofmodern varieties and economic integration broughtseveral negative impacts (Lappe, Collins, & Rosset,1998; Shiva, 1991), including the following:

Bulletin of Science, Technology & Society, Vol. 25, No. 4, August 2005, 361-371DOI: 10.1177/0270467605277291Copyright 2005 Sage Publications

The Green Revolution involved the promotionof a package that included modern varieties(MVs), fertilizer, and irrigation, marginalizinga great number of resource-poor farmers whocould not afford the technology.

In areas where farmers adopted the packagestimulated by government extension and creditprograms, the spread of MVs greatly increasedthe use of pesticides, often with serious healthand environmental consequences.

Enhanced uniformity caused by sowing largeareas to a few MVs increased risk for farmers.Genetically uniform crops proved more sus-ceptible to pests and diseases, and also im-proved varieties did not perform well in mar-ginal environments where the poor live.

The spread of MVs was accompanied by a sim-plification of traditional agroecosystems and atrend toward monoculture that affected dietarydiversity, thus raising considerable nutritionalconcerns.

The replacement of folk varieties also repre-sented a loss of cultural diversity as many vari-eties are integral to religious or communityceremonies.

Ecological theory predicts that the introduction oftransgenic crops will probably replicate or further ag-gravate the effects of MVs on the genetic diversity oflandraces and wild relatives in areas of crop origin anddiversification and therefore affect the cultural threadof rural communities (Altieri, 2000).

Despite these warnings, proponents of biotechnol-ogy argue that transgenic crops are a strategy toimproving conventional farming methods by reducingthe use of synthetic chemical pesticides and that there-fore comprises a production system that is compatiblewith more environmentally benign forms of agricul-ture. Globally, the cropland area planted to GM cropsgrew from 67.7 million hectares in 2003 to 81.0 mil-lion hectares in 2004, exhibiting a growth rate of 20%.The bulk of the production of the dominant crops (soy-bean, maize, canola, and cotton) is still concentrated inthe United States, Argentina, and Canada, althoughsignificant adoption is occurring in Brazil, China, Par-aguay, India, and South Africa. Herbicide-resistant(HT) soybean occupies 60% of the global biotech area(48 million hectares), followed by insect-resistant (Bt)maize, which occupies 23% of the biotech area(James, 2004).

On the other hand, organic agriculture is practicedin almost all countries of the world, and its share ofagricultural land and farms is growing. According to areport by Food and Agriculture Organization of theUnited Nations (FAO; 2002), the total organicallymanaged area is more than 24 million hectares world-wide. Australia/Oceania holds 42% of the worldsorganic land, followed by Latin America (24.2%) andEurope (23%). Oceania and Latin America concen-trate much of the land under organic management, butthis is due to the fact that extensive organic livestocksystems dominate in Australia (about 10 million hect-ares) and in Argentina (almost 3 million hectares).Europe and Latin America have the highest numbersof organic farms, and in Asia and Africa, organic farm-ing is growing, and both regions are characterized bysmall farms. In Europe, organic agriculture is increas-ing rapidly. In Italy, there are about 56,000 organicfarms occupying 1.2 million hectares. In Germanyalone, there are about 8,000 organic farms occupyingabout 2% of the total arable land, and in Austria about20,000 organic farms account for 10% of total agricul-tural output. In the United Kingdom, the organic mar-ket is displaying growth rates of 30% to 50% perannum. Although in the United States organic farmsoccupy 0.25% of the total agricultural land, organicacreage doubled between 1992 and 1997, and in 1999the retail organic produce industry generated $6 bil-lion in sales. In California, organic foods are one of thefastest growing segments of the agricultural economy,with retail sales growing at 20% to 25% per year forthe past 6 years. Cuba is the only country undergoing amassive conversion to organic farming, promoted bythe drop of fertilizer, pesticide, and petroleum importsafter the collapse of trade relations with the Soviet blocin 1990. By massively promoting agroecological tech-niques in both urban and rural areas, productivitylevels in the island have recovered substantially.

Major Differences Between Organicand Transgenic Agriculture

Organic farming is a production system that sus-tains agricultural productivity by avoiding or largelyexcluding synthetic fertilizers and pesticides(Lampkin, 1990). External resources, such as com-mercially purchased chemicals and fuels, are replacedby resources found on or near the farm. These internalresources include solar or wind energy, biological pestcontrols, and biologically fixed nitrogen and othernutrients released from organic matter or soil reserves.

362 BULLETIN OF SCIENCE, TECHNOLOGY & SOCIETY / August 2005

Thus, organic farmers rely heavily on the use of croprotations, crop residues, animal manures, legumes,green manures, off-farm organic wastes, mechanicalcultivation, mineral-bearing rocks, and aspects of bio-logical pest control to maintain soil productivity andtilth, to supply plant nutrients, and to control insectpests, weeds, and diseases. Most small and mediumsize organic farmers feature legume-based rotations,use of compost, and a series of diversified croppingsystems such as cover crops or strip cropping, includ-ing crop-livestock mixtures. Research shows thatthese systems exhibit acceptable yields, conserveenergy, and protect the soil while inducing minimalenvironmental impact.

In contrast, GM cropping systems are characterizedby monoculture systems that may reduce the use eitherof herbicides or a particular insecticide but that are stillheavily dependent on the use of synthetic fertilizersand other pesticides to suppress insects or weeds thatthe GM crop does not control. Although such systemsmay prove to be productive and in some cases econom-ically profitable, several scientists argue that herbi-cide-resistant crops (HRCs) and Bt crops have been apoor choice of traits to feature given predicted envi-ronmental problems and the issue of resistance evolu-tion. In fact, there is enough evidence to suggest thatboth these types of crops are not really needed toaddress the problems they were designed to solve. Onthe contrary, they tend to reduce the pest managementoptions available to farmers. To the extent that trans-genic crops further entrench the current monoculturalsystem, they impede farmers from using a plethora ofalternative methods (Krimsky & Wrubel, 1996).

GM crops further lead to agricultural intensifica-tion, and ecological theory predicts that as long astransgenic crops follow closely the pesticide para-digm, such biotechnological products will do nothingbut reinforce the pest ic ide treadmil l inagroecosystems, thus legitimizing the concerns thatmany environmentalists and some scientists haveexpressed regarding the possible environmental risksof genetically engineered organisms. The most impor-tant difference between organic farming and biotechagriculture is that organic farmers rely on the ecologi-cal services of agrobiodiversity and thus avoid the useof chemical fertilizers and pesticides in their farmingoperations. Conversely, GM crop farmers promotegenetic uniformity and monocultures and do notrestrict the use of chemical pesticides and fertilizers.Clearly there are sharp contrasts between organic andbiotech agriculture (Table 1).

Most studies assessing the environmental impactsof transgenic crops have concentrated in comparingconventional and transgenic crops, and resultingreports about population decreases of a particular spe-cies are usually an underestimate as comparisons usu-ally did not include organic systems. Such reductioniststudies were not able to capture the full spectrum ofimpacts GM crops on biodiversity, and neither did theyaddress the effects of biodiversity reductions onagroecosystem processes such as nutrient cycling orpest regulation. Merely examining the effects of GMcrops on the abundance of a few target species does notprovide ecological information of mush use, espe-cially if those studies exclude agroecosystems thatexpress high levels of biodiversity.

The rationale behind each system is substantiallydifferent: Organic farms are based on the assumptionthat biodiversity is an integral part of agroecosystemdesign and that at any given time some of the acreage isplanted with legume green manures that will beplowed under or be grazed by cattle, whose manurewill be returned to the soil. The transgenic farms arebased on a profoundly different assumption: Their sur-vival depends on the access to genetic resources thatwill provide key traits to engineered plants and to anagrochemical factory somewhere that is consumingvast amounts of fossil fuels and emitting greenhousegases.

The Agroecological Basis ofIncompatibility Between GM and

Organic Forms of Agriculture

For promoters of biotechnology, chemical drift andpotential gene flow problems do not mean that the con-cept of coexistence between different production sys-tems is unworkable but rather involves managing con-flicting values and also requires certain technicalissues to be resolved such as preventing chemical driftor minimizing the physical transfer of materialbetween GM and non-GM systems (e.g., pollen from aGM plant fertilizing a neighbors non-GM crop or thepresence of GM pollen in honey, etc). But the prob-lems are much deeper than that because the differencesbetween biotechnology-based and organic agricultureare so fundamental that both systems are based ontotally different ecological rationales. In fact, as cur-rently implemented, the two forms of agriculture are inconflict because international organic standards pro-hibit the use of genetically engineered inputs and do

Altieri / MYTH OF COEXISTENCE 363

not tolerate GM crop pollen drift that may reduce themarketability of organic crops.

The biodiversity associated with agricultural sys-tems is already being affected significantly by conven-tional agricultural intensification, with many speciesof farmland birds, butterflies, and plants having de-clined substantially during the past 50 years in agricul-tural landscapes worldwide. Using certain types ofGM crops has the potential to reduce biodiversity fur-ther by increasing such intensification. There are alsopotential risks to biodiversity arising from gene flowand toxicity to nontarget organisms from some GMcrops. In fact, there are several widely accepted envi-ronmental drawbacks associated with the rapid de-ployment and widespread commercialization of suchcrops in large monocultures, including the following(Kendall et al., 1997; Rissler & Mellon, 1996; Snow &Moran, 1997):

a. the spread of transgenes to related weeds orconspecifics via crop-weed hybridization;

b. reduction of the fitness of nontarget organ-isms (especially weeds or local varieties)through the acquisition of transgenic traitsvia hybridization;

c. the rapid evolution of resistance of insect pestssuch as Lepidoptera to Bt;

d. accumulation of the insecticidal Bt toxin, whichremains active in the soil after the crop is plowed

under and binds tightly to clays and humicacids;

e. disruption of natural control of insect peststhrough intertrophic-level effects of the Bt toxinon natural enemies;

f. unanticipated effects on nontarget herbivorousinsects (i.e., monarch butterflies) through depo-sition of transgenic pollen on foliage of sur-rounding wild vegetation (Losey, Rayor, &Cater, 1999); and

g. vector-mediated horizontal gene transfer andrecombination to create new pathogenicorganisms.

By further examining the fundamental premises onwhich organic farming operates, it is clear that GMcrops are totally incompatible with agroecologicallybased approaches. By describing the main features oforganic farming, it is possible to visualize why GM ag-riculture is a model of farming that is incompatiblewith the tenets of a sustainable agriculture as it ex-pands at the expense of other production forms.

Organic agriculture relies on diversification strate-gies such as polycultures, rotations, cover crops, andanimal integration to optimize productivity andachieve agroecosystem health. Transgenic crops (es-pecially HRCs) condemn farmers to monocultures asherbicides such as Roundup are broad spectrum, elim-


Table 1. Characteristics of Organic Farming and Genetically Modified Based Agriculture

Characteristics Biotech Organic

Petroleum dependency High MediumLabor requirements Low, hired Medium, family or hiredManagement intensity High Low-mediumIntensity of tillage High, except in no-till systems Low (no till without herbicides) to mediumPlant diversity Low Medium to highCrop varieties Genetically modified, genetically Hybrid or open pollinated, variety mixtures

homogenous, one variety over large areasSource of seeds Multinational corporations, all purchased, Purchased from small seed companies, some

patented savedIntegration of crops and livestock None Little (use of manure) to crop-livestock mixturesInsect pests Very unpredictable UnpredictableInsect management Insect-resistant crops Integrated pest management, biopesticides,

biocontrol, habitat managementWeed management Herbicide-resistant crops, chemical, tillage Cultural control, rotationsDisease management Chemical, vertical resistance Antagonists, horizontal resistance, multiline

cultivarsPlant nutrition Chemical, fertilizers applied in pulses, Microbial biofertilizers, organic fertilizers,

open systems semi-open systemsWater management Large-scale irrigation Sprinkler and drip irrigation, water-saving

systems

inating all vegetation except the engineered crop. Un-der such scheme, it is impossible to promote designsthat involve intercropping and rotational systemswhen associated crops are susceptible to the herbicideor its residues. Perhaps the greatest problem of usingHRCs to solve weed problems is that they steer effortsaway from alternatives such as crop rotation or covercrops, encouraging maintenance of simplified crop-ping systems dominated by one or two annual species(Paoletti & Pimentel, 1996). Crop rotation not only re-duces the need for herbicides but also improves soiland water quality, minimizes requirements for syn-thetic nitrogen fertilizer, regulates insect pest andpathogen populations, increases crop yields, and re-duces yield variance (Altieri, 1995). Thus, to the ex-tent that transgenic HRCs inhibit the adoption ofrotational crops and cover crops they hinder thedevelopment of sustainable agricultural systems.

The rapid spread of transgenic crops further threat-ens crop diversity by promoting large monocultures ina rapid scale, leading to further environmental simpli-fication and genetic uniformity. History has repeatedlyshown that uniformity characterizing agriculturalareas sown to a smaller number of varieties, as in thecase of GM crops, is a source of increased risk forfarmers as the genetically homogeneous fields tend tobe more vulnerable to disease and pest attack (Robin-son, 1996). Examples of disease epidemics associatedwith homogeneous crops abound in the literature,including the $1 billion loss of maize in the UnitedStates in 1970 and the 18 million citrus trees destroyedby pathogens in Florida in 1984 (Thrupp, 1998).

Organic agriculture privileges the use of local vari-eties adapted to specific conditions and to low inputmanagement. Clearly, the use of genetic diversity byorganic farmers has special significance for the main-tenance and enhancement of productivity of farmingsystems as diversity provides security to farmersagainst diseases, pests, droughts, and other stressesand also allows farmers to exploit the full range ofagroecosystems existing in each region. Gene ex-changes pose major threats to centers of diversity; inbiodiverse farming systems, the probability for trans-genic crops of finding sexually compatible wild rela-tives is very high. Unwanted gene flow from GM cropsmay compromise native crop biodiversity (and there-fore the associated systems of agricultural knowledgeand practice along with the ecological and evolution-ary processes involved) and may pose a threat worsethan cross-pollination from conventional (non-GM)

seed. In fact, some researchers believe that DNA fromengineered crops is likely to confer an evolutionaryadvantage, and if transgenes do persist, they may actu-ally prove disadvantageous to farmers and crop diver-sity (Stabinski & Sarno, 2001). Can genetically engi-neered plants actually increase crop production and atthe same time repel pest, resist herbicides, and conferadaptation to stressful factors commonly faced bysmall farmers? At issue is the possibility that traits im-portant to indigenous farmers (resistance to drought,competitive ability, performance on intercrops, stor-age quality, etc) could be traded for transgenic quali-ties that may not be important to farmers (Jordan,2001). Under this scenario, risk could increase andfarmers would lose their ability to adapt to changingbiophysical environments and produce relativelystable yields with a minimum of external inputs whilesupporting their communities food security.

A major ecological risk is that large-scale releasesof HT transgenic crops may promote transfer oftransgenes from crops to other plants, which thencould become weeds (Snow & Moran, 1997).Transgenes that confer significant biological advan-tage may transform wild/weedy plants into new ormore invasive weeds (Rissler & Mellon, 1996). Thebiological process of concern here is introgressionhybridization among distinct plant species. This isworrisome given that a number of crops are grown inclose proximity to sexually compatible wild relatives(Lutman, 1999). Extreme care should be taken in plantsystems exhibiting easy cross-pollination, such asoats, barley, sunflowers, and wild relatives, andbetween rapeseed and related crucifers (Snow &Moran, 1997). Bt crops can also contribute to the cre-ation of super weeds. Snow et al. (2003) showed thatwhen a transgene coding for an insecticidal compoundmoved from commercial transgenic sunflower intoweedy sunflowers, the weeds experienced reducedherbivory and produced more seeds, thus transgeneescape is making a weed problem worse.

The transfer of genes from transgenic crops toorganically grown crops poses a specific problem toorganic farmers. Organic certification depends on thegrowers being able to guarantee that their crops haveno inserted genes. Crops able to outbreed, such asmaize or oilseed rape, will be affected to the greatestextent, but all organic farmers are at risk of geneticcontamination. There are no regulations that enforceminimum isolating distances between transgenic andorganic fields (Royal Society, 1998).


Organic farms depend on the presence of functionalbiodiversity in their farms as it provides ecologicalservices such as pest regulation, pollination, nutrientcycling, and so on. During the past half-century, cropdiversity has declined precipitously in conventionalhigh-input farming systems in the United States andother industrialized countries as well as in theagroexport regions of the developing world. Such re-duction in crop diversity has resulted in the simplifica-tion of the landscape. The expansion of monocultureshas decreased abundance and activity of natural ene-mies due to the removal of critical food resources andoverwintering sites (Altieri & Nicholls, 2004). Manyscientists are concerned that with accelerating rates ofhabitat removal, the contribution to pest suppressionby biocontrol agents using these habitats is decliningand consequently agroecosystems are becoming in-creasingly vulnerable to pest invasion and outbreaks.In general, monocultures do not constitute good envi-ronments for natural enemies. Such simple crop sys-tems lack many of the resources, such as refuge sites,pollen, nectar, and alternative prey and hosts, that nat-ural enemies need to feed and reproduce; therefore,insect pests usually drive and reach pest outbreakproportions.

Total weed removal associated with herbicide-resistant crops will surely aggravate pest problemsassociated with vegetation-free monocultures. Themassive use of Roundup and other broad-spectrumherbicides eliminates many weed species that offermany important requisites for natural enemies such asalternative prey/hosts, pollen, or nectar as well asmicrohabitats that are not available in weed-freemonocultures (Altieri & Nicholls, 2004). In the past20 years, research has shown that outbreaks of certaintypes of crop pests are less likely to occur in weed-diversified crop systems than in weed-free fields,mainly due to increased mortality imposed by naturalenemies. Crop fields with a dense weed cover and highdiversity usually have more predaceous arthropodsthan do weed-free fields. The successful establishmentof several parasitoids usually depends on the presenceof weeds that provide nectar for the adult femalewasps. Relevant examples of cropping systems inwhich the presence of specific weeds has enhanced thebiological control of particular pests were reviewed byAltieri and Nicholls (2004). A literature survey byBaliddawa (1985) showed that population densities of27 insect pest species increased in weed-free cropscompared to weedy crops. Obviously, total elimina-tion of weeds, as it is common practice under HRC

crops, can have major ecological implications forinsect pest management.

Organic agriculture promotes small to mediumfarms that promote local and economically viablefamily farming. During the postwar period, numbersof farms in the United States experienced a sharp de-cline. More than 4 million farmers have gone out ofbusiness in the past 50 years, an average of 219 farmslost per day. The reality is that U.S. farmers have in-creasingly been caught in a cost-price squeezewhereby the ballooning costs of modern farm technol-ogy have consistently swallowed any increases in farmincome. While food prices have long been stagnantdue to overproduction, costs of manufactured inputshave soared. Farmers have been driven into debt tocover the costs of $40,000 tractors and $100,000 har-vesters, and by and large their slim profit margins havenot been enough to cover debt service, thus leading towaves of bankruptcies and foreclosures. It is importantto note that both overproduction and high productioncosts are results of the same productionist technology,which is thus responsible for both the cost and theprice side of the economic squeeze affecting farmers(Rosset, 2002).

Biotechnological innovations are a prime exampleof a technology that promotes economies of scale andconcentration of land in larger holdings throughout theworld, both in the North and the South. In this regard, itis useful to examine the realities faced by Iowa farmerswho live in the heartland of U.S. transgenic corn andsoy. Although weeds are an annoyance, the real prob-lem the farmers face is falling farm prices, drivendown by long-term overproduction.

From 1990 to 1998, the average price of a metric tonof soybeans decreased 62%, and returns over nonlandcosts declined from $530 to $182 per hectare, a 66%drop. Faced with falling returns per hectare, farmershave had no choice but to get big or get out. Only byincreasing acreage to compensate for falling per-acreprofits can farmers stay in business. Any technologythat facilitates getting big will be seized on, even ifshort-term gains are wiped out by prices that continueto fall as the industrial agricultural model expands. Forthese Iowa farmers, reductions in return per unit ofcropland have reinforced the importance of herbicideswithin the production process as they reduce timedevoted to mechanical cultivation, allowing a givenfarmer to farm more acres. A survey of Iowa farmersconducted in 1998 indicated that the use of glyphosatewith glyphosate-resistant soybean varieties reduced


weed control costs by nearly 30% compared with con-ventional weed management for nontransgenic variet-ies. However, yields for the glyphosate-resistant soy-beans were about 4% lower, and net returns per unitland area from glyphosate resistant and conventionalsoybeans were nearly identical (Altieri, 2004).

From the standpoint of convenience and cost reduc-tion, the use of broad-spectrum herbicides in combina-tion with herbicide-resistant varieties appeals to farm-ers. Such systems fit well with large-scale operations,no-tillage production, and subcontracted chemicalapplications. However, from the standpoint of price,any penalty for transgenic varieties in the marketplacewill make the impact of existing low prices evenworse. Taking into account that American exports ofsoybeans to the European Union plummeted from 11million to 6 million tons in 1999 due to rejection ofgenetically modified organisms (GMOs) by Europeanconsumers, it is easy to predict disaster for farmersdependent on transgenic crops (Brummer, 1998).

The integration of the seed and chemical industriesappears to accelerate increases in per-acre expendi-tures for seeds plus chemicals, delivering significantlylower returns to growers. Companies developingherbicide-tolerant crops are trying to shift as muchper-acre cost as possible from the herbicide onto theseed-by-seed costs and technology charges. Increas-ingly, price reductions for herbicides will be limited togrowers purchasing technology packages. In Illinois,the adoption of herbicide-resistant crops makes for themost expensive soybean seed-plus-weed managementsystem in modern historybetween $40 and $60 peracre depending on fee rates, weed pressure, and so on.Just 3 years ago, the average seed-plus-weed controlcosts on Illinois farms was $26 per acre and repre-sented 23% of variable costs. Today, they represent35% to 40% (Carpenter & Gianessi, 1999). Farmersmay experience significant savings in herbicide costs(up to 30%), but the difference is in seed cost. In 1998,Iowa farmers spent $26.42 per acre on geneticallyengineered seeds while the cost of conventional seedwas only $18.89 per acre. Many farmers are willing topay for the simplicity and robustness of the new weedmanagement system, but such advantages may beshort-lived as ecological problems arise.

In Argentina, virtually all of its 15 million hectaresof soybean has been planted with herbicide-tolerantsoybean. Although the transgenic area increased, sodid the use of glyphosate, big tractors (combines), andacreage under no-till farming. This agricultural trans-formation has occurred in a context of profit margins

falling down by 50% between 1992 and 1999, whichdrove many farmers out of business. Farmers areindebted with bank loans linked to high interest ratesto pay back for investments in machinery, chemicalinputs, and seeds. This situation has favored the estab-lishment of large holdings and the disappearance ofsmaller farmers. Just in 7 years, the number of farms inLa Pampa declined from 170,000 to 116,000, whilethe average size of farms increased from 243 to 538hectare in 2003. The 126% increase of soybean acre-age in the past decade also occurred at the expense ofsignificant areas previously devoted to fruits, dairy,cattle, maize, wheat, sunflower, cotton, sugarcane, andothers. When the economic crisis hit the country, therewas not much food to offer the growing hungry popu-lation other than soybean, a food that Argentineanshave never been accustomed to consuming (Pengue,2000).

In Europe, a recent study by the Institute for Pro-spective Technological Studies of the EU JointResearch Centre (Bock et al., 2002) stated that allfarmers would face high additional, in some casesunsustainable costs of production if GM crops werecommercially grown in a large scale. The study pre-dicted that commercialization of GM oilseed rape andmaize and to a lesser extent potatoes will increasecosts of farming for conventional and organic farmersat a range between 10% and 41% of farm prices for oil-seed rape and between 1% and 9% for maize and pota-toes. Under such a scenario, coexistence would bevery difficult as seed and crop purity from GM crops ata detection level of 0.1% would be virtually impossi-ble in most cases, namely, all products and seeds of oil-seed rape and maize would be contaminated with GMto a certain extent. Unfortunately, this seems to be thecase in the United States, where recent tests on localvarieties of corn, soybeans, and canola have found per-vasive transgenic contamination (Mellon & Rissler,2004).

Small organic farms are more productive and envi-ronmentally sound than large-scale conventional andtransgenic farms. This GM agricultureinduced trendtoward land consolidation into large farms not onlydisplaces farmers but also attempts against the diver-sity of production of a country and consequently itsfood security. Designed to maximize the productivityof a single resource that is scarce in the First Worldlaborthis technology has proven to be wasteful ofland and capital. When exported to countries withchronic unemployment and little capital, it rapidly


leads to enormous rural-urban migration, social prob-lems, and the penetration of agriculture by foreigncapital (Rosset, 1999). The monoculture/large farmtrap is also an underlying cause of low productivity inmost countries as large farms almost always displaymuch lower productivity per unit area than smallerfarms.

Large farmers tend to plant monocultures becausethey are the simplest to manage with heavy machinery.Small farmers on the other hand, especially in theThird World, are much more likely to plant cropmixturesintercroppingwhere the empty nichespace that would otherwise produce weeds instead isoccupied by other crops. They also tend to combine orrotate crops and livestock, with manure serving toreplenish soil fertility. Such integrated farming sys-tems produce far more per unit area than domonocultures. Although the yield per unit area of onecropcorn, for examplemay be lower on a smallfarm than on a large monoculture, the total output perunit area, often composed of more than a dozen cropsand various animal products, can be much higher.Therefore, total output rather than yield is a betterparameter to compare yields of large and small farms.Total output is the sum of everything a small farmerproduces: various grains, fruits, vegetables, fodder,animal products, and so on. Whereas yield almostalways biases the results toward larger farms, total out-put allows us to see the true productivity advantage ofsmall farms (Rosset, 1999).

Data show that small farms almost always producefar more agricultural output per unit area than largerfarms both in industrial and developing countries. Thisis now widely recognized by agricultural economistsacross the political spectrum as the inverse relation-ship between farm size and output. In the UnitedStates, the smallest farms, those of 27 acres or less,have more than 10 times greater dollar output per acrethan larger farms. Although this is in large part due tothe fact that smaller farms tend to specialize in high-value crops such as vegetables and flowers, it alsoreflects relatively higher labor and input efficiency andthe yield-enhancing effects of more diverse farmingsystems (Rosset, 1999).

Research has shown that organic farms can be asproductive as conventional ones but without usingagrochemicals. They also consume less energy andsave soil and water. A strong body of evidence sug-gests that organic methods can produce enough foodfor alland do it from one generation to the next with-out depleting natural resources or harming the envi-

ronment. In 1989, the National Research Councilwrote up case studies of eight organic farms thatranged from a 400-acre grain/livestock farm in Ohio to1,400 acres of grapes in California and Arizona. Theorganic farms average yields were generally equal toor better than the average yields of the conventionalhigh-intensity farms surrounding themonce againshowing they could be sustained year after year with-out costly synthetic inputs (National ResearchCouncil, 1994).

Recent long-term studies such as the one conductedat the Farming Systems Trial at the Rodale Institute, anonprofit research facility near Kutztown, Pennsylva-nia, tested three kinds of experimental plots side byside for nearly two decades. One is a standard high-intensity rotation of corn and soybeans in which com-mercial fertilizers and pesticides have been used.Another is an organic system in which a rotation ofgrass/legume forage has been added and fed to cows,whose manure is then returned to the land. The third isan organic rotation in which soil fertility has beenmaintained solely with legume cover crops that havebeen plowed under. All three kinds of plots have beenequally profitable in market terms. Corn yields havediffered by less than 1%. The rotation with manure hasfar surpassed the other two in building soil organicmatter and nitrogen, and it has leached fewer nutrientsinto groundwater. During the record drought of 1999,the chemically dependent plots yielded just 16 bushelsof soybeans per acre; the legume-fed organic fieldsdelivered 30 bushels per acre, and the manure-fedorganic fields delivered 24 bushels per acre (FAO,2002).

In what must be the longest running organic trial inthe world150 yearsEnglands RothamstedExperimental Station (also known as the Institute ofArable Crops Research) reports that its organicmanured plots have delivered wheat yields of 1.58 tonsper acre, compared to synthetically fertilized plots thathave yielded 1.55 tons per acre. That may not seemlike much, but the manured plots contain six times theorganic matter found in the chemically treated plots.FIBL (Research Institute of Organic Agriculture) sci-entists in Central Europe conducted a 21-year study ofthe agronomic and ecological performance ofbiodynamic, organic, and conventional farming sys-tems. They found crop yields to be 20% lower in theorganic systems, although input of fertilizer andenergy was reduced by 31% to 53% and pesticideinput by 97%. They concluded that enhanced soil fer-tility and higher biodiversity found in organic plots


rendered these systems less dependent on externalinputs (Mader et al., 2002).

In terms of environmental benefits, the evidenceshows that organic farming conserves naturalresources and protects the environment more than con-ventional farming. Soil erosion rates are lower inorganic farms, and levels of biodiversity are higher inorganic farming systems than in conventional ones.Most practitioners of organic agriculture believe thatorganic farms have positive impacts on biodiversityand that farmland under organic agriculture does notexhibit the dramatic declines of many animal speciesas observed in areas dominated by conventional agri-culture. In a recent survey of the literature, Hole et al.(2005) reviewed 76 published studies and found thatspecies abundance and/or richness across a wide rangeof taxa was higher on organic farms than on locallyrepresentative conventional farms. Of particularimportance from a conservation perspective is thatmany of these differences apply to species known tohave experienced declines in range and/or abundanceas a consequence of past agricultural intensification, asignificant number of which are now the subject ofdirect conservation legislation (e.g., skylark, lapwing,greater and lesser horseshoe bat, corn buttercupRanunculus arvensis, and red hem-nettle are all U.K.government Biodiversity Action Plan species). Thesebiodiversity benefits are likely to derive from the spe-cific environmental features and management prac-tices employed within organic systems, which areeither absent or only rarely used in the majority ofconventional systems.

Reganold, Glover, Andrews, and Hinman (2001)assessed the sustainability of organic, conventional,and integrated apple production systems in Washing-ton State from 1994 to 1999. All three systems gavesimilar apple yields, although organic systems per-formed better in dry years. The organic and integratedsystems had higher soil quality and potentially lowernegative environmental impact than the conventionalsystem. The results from this study show that organicand integrated apple production systems in Washing-ton State are not only better for soil and the environ-ment than their conventional counterpart but havecomparable yields and for the organic system, higherprofits and greater energy efficiency. Although cropyield and quality are important products of a farmingsystem, the benefits of better soil and environmentalquality provided by the organic and integrated produc-tion systems are equally valuable and oftenoverlooked.

Conclusions and Recommendations

The available, independently generated scientificinformation suggests that because the massive use oftransgenic crops poses substantial potential ecologicalrisks, GM crops are not compatible with organic farm-ing or other alternative forms of production. GM agri-culture undermines coexistence mechanisms as it prej-udices the ability of farmers to manage their land forthe benefit of biodiversity or natural resources, forexample by requiring increased use of herbicides tocontrol volunteers or by reducing farmers choice ofrotations or other diversification managementpractices.

The first important argument against the concept ofcoexistence is that the movement of transgenesbeyond their intended destinations and hybridizationwith weedy relatives and contamination of other non-GM crops is a virtual certainty (Marvier, 2001).Removing or recalling genes once they have escapedinto natural gene pools is impossible. There are noadequate safeguards against gene flow between theGMO and native organisms where transgenes arelikely to affect fitness, decrease genetic diversity, orincrease toxicity (Steinbrecher, 1996). Although thepreferred method should be to avoid releasing trans-genic organisms in areas with sexually compatiblewild relatives, there is no guarantee that this will hap-pen due to corporate pressures, lack of biosafetyregulations, human error, or corruption.

The environmental effects are not limited to pestresistance and creation of new weeds or virus strainsvia gene flow (Kendall et al., 1997). Direct risks fromGMOs may include toxicity of transgenic organismsto wildlife, competitive displacement of native speciesby transgenic organisms or hybrids with wild species,and effects on soil and aquatic ecosystems. Indirectrisks include changes in land and water use and man-agement that are detrimental to the wildlife that usefarmland, woodland, freshwater, or the seas. It isknown that transgenic crops can produce environmen-tal toxins that move through the food chain and alsoend up in the soil where they bind to colloids and retaintheir toxicity, affecting invertebrates and possiblynutrient cycling (Altieri, 2000). No one can really pre-dict the long-term impacts on agrobiodiversity and theprocesses they mediate from the massive deploymentof such crops, an unfortunate trend as most scientistsfeel that such knowledge was crucial to have beforebiotechnological innovations were upscaled to actuallevels.


Although there is a clear need to further assess theseverity, magnitude, and scope of risks associated withthe massive field release of transgenic crops, transgenemovement via pollen and seed is already so pervasivethat the only possible safe route to secure an agricul-ture free of GM contamination is to create GMO-freeisolated geographical areas and to maintain some non-GM seed lineages for cases where people desire crop-ping systems that are free of GM traits. Moreover, therepeated use of transgenic crops in an area may resultin cumulative effects such as those resulting from thebuildup of toxins in soils, which will make those soilsunsuitable for other forms of agriculture for anunknown number of years. Decreases in pesticide useare not acceptable as proxies for environmental bene-fits as this does not mean that the GM crop do notexudate, toxins, or associated herbicides do not exertmultitrophic effects and impacts on agroecosystemfunction.

There is no doubt that the large-scale landscapehomogenization with transgenic crops will exacerbatethe ecological problems already associated withmonoculture agriculture (Altieri, 2000). Unques-tioned expansion of this technology into developingcountries may not be wise or desirable. There isstrength in the agricultural diversity of many of thesecountries, and it should not be inhibited or reduced byextensive monoculture, especially when conse-quences of doing so results in serious social and envi-ronmental problems (Altieri, 2003). Under conditionsof poverty, marginalized rural populations have nooption but to maintain low-risk agroecosystems thatare primarily structured to ensure local food security.Farmers in the margins have a need to continue pro-ducing food for their local communities in the absenceof modern inputs, and this can be reached by preserv-ing in situ ecologically intact, locally adaptedagrobiodiversity. For this, it may be necessary to main-tain geographically isolated areas of traditionalagroecosystems and pools of genetic diverse materialas these islands of traditional agriculture can act asextant safeguards against the potential ecological fail-ure derived from an inappropriate agricultural mod-ernization led by GM crops. It is precisely the ability togenerate and maintain diverse crop genetic resourcesthat offer unique niche possibilities to marginalfarmers that cannot be replicated by other farmers withuniform cultivars in the more favorable lands. Thisdifference inherent to traditional systems can bestrategically used by exploiting unlimited opportuni-ties that exist for linking traditional agrobiodiversity

with local/national/international markets as long asthese activities are carefully planned and remain undergrass-roots control.

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Miguel A. Altieri, professor of agroecology at the Universityof California, Berkeley, has championed the application ofagroecology for the development of biodiverse sustainablefarming systems in California and Latin America. His re-search on the role of biodiversity on agroecosystem functionis well known through his books and journal articles.


Altieri 2005 the Myth of Coexistence GMO and Agroecology

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