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Genetically Engineered Crops: Separating the Myths From the Reality Miguel A. Altieri Bulletin of Science Technology Society 2001; 21; 130 The online version of this article can be found at: http://bst.sagepub.com

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Perspectives: Macro STS

Genetically Engineered Crops: Separating the Myths From the Reality Miguel A. Altieri University of California, Berkeley

Until about four decades ago, crop yields in U.S. agricultural systems depended on internal resources, recycling of organic matter, built-in biological control mechanisms, and rainfall patterns. Agricultural yields were modest but stable. Production was safeguarded by growing more than one crop or variety in space and time in a field as insurance against pest outbreaks or severe weather. Inputs of nitrogen were gained by rotating major field crops with legumes. In turn, rotations suppressed insects, weeds, and diseases by effectively breaking the life cycles of these pests. A typical corn belt farmer grew corn rotated with several crops, including soybeans, and small grain production was intrinsic to maintain livestock. Most of the labor was done by the family with occasional hired help, and no specialized equipment or services were purchased from off-farm sources (Altieri, 1996; Audirac, 1997). In the developing world, small farmers developed even more complex and biodiverse farming systems guided by indigenous knowledge that has stood the test of time (Thrupp, 1998). In these types of farming systems, the link between agriculture and ecology was quite strong, and signs of environmental degradation were seldom evident. But as agricultural modernization progressed, the ecology-farming linkage was often broken as ecological principles were ignored and/or overridden. As profit rather than people’s needs or environmental concerns shaped the modes of agricultural production, agribusiness interests and prevailing policies favored large farm size, specialized production, crop monocultures, and mechanization. Today, monocultures have increased dramatically worldwide, mainly through the geographical expansion of land yearly devoted to single crops. Thus, monoculture has implied the simplification of bio-

diversity, the end result being an artificial ecosystem requiring constant human intervention in the form of agrochemical inputs that in addition to temporarily boosting yields result in a number of undesirable environmental and social costs. Aware of such effects, several agricultural scientists have arrived at a general consensus that modern agriculture confronts an ecological crisis (Conway & Pretty, 1991). The yearly loss of yields due to pests in many crops (reaching about 30% in most crops) despite the substantial increase in the use of pesticides (about 500 million kg of active ingredient worldwide) is a symptom of the environmental crisis affecting agriculture. It is well known that cultivated plants grown in genetically homogenous monocultures do not possess the necessary ecological defense mechanisms to tolerate the effect of outbreaking pest populations (Altieri, 1994). When these agricultural models were exported to Third World countries through the so-called Green Revolution, environme