Environmental Engineering Reference
In-Depth Information
While the principal environmental impacts of shifting corn trade relate to biodiversity,
Mexico has a signi
cant number of modern growers, geographically concentrated in the
northern state of Sinaloa. In a detailed case study for the North American Commission for
Environmental Cooperation, de Ita Rubio (2003) assessed the environmental impacts of
expanding industrial maize production in Sinaloa. Due to price incentives and other market
distortions that temporarily favored maize and bean production, modern producers dra-
matically increased production in the mid-1990s. With the removal of price supports, irri-
gated land planted in maize dropped 40 percent nationally between 1989 and 2001 (de Ita
Rubio, 2003). There was a decline in acreage in Sinaloa as well, but a tripling of yields
allowed production in Sinaloa to rise to ten times its pre-NAFTA level (SIACON, 2003).
Not surprisingly, the impacts mirror those in the USA: high chemical use, with its
accompanying environmental impacts; and unsustainable water use for heavily irrigated
farms. GM maize cultivation is still banned in Mexico, so potential damage from Bt maize
is not present in Sinaloa at the time of writing.
While Sinaloa's share of national production increased dramatically during the 1990s,
production in more traditional sectors of Mexico's maize economy has stagnated or
declined. Trade threatens Mexican maize diversity in two ways. First, and most impor-
tant, the
fi
ood of imports from the USA has brought producer prices down nearly
50 percent, increasing economic pressure on marginal maize farmers. If they leave the
land or leave maize farming, the traditional knowledge and practices that sustain this
resource will go with them.
In Mexico, the map of rural poverty closely mirrors the map of genetic diversity, with
the poorest and most diverse farms concentrated in the southern and eastern parts of the
country. This is not surprising. Traditional agricultural practices tend to prevail in more
marginal environments, where native landraces have been selected over the generations to
provide unique advantages not available in high-yield hybrid seeds. The map of cultural
diversity would also show similar shadings, as indigenous farmers concentrated in the
southeastern section of the country tend to use the widest diversity of seeds while also
su
fl
ering the highest levels of poverty and marginalization.
While many - including some in the Mexican government - predicted that NAFTA
would lead to an exodus from maize, this has largely not occurred. Data suggest that pro-
duction has remained relatively constant, and even increased in some of the states domi-
nated by traditional production (Ackerman et al., 2003).
Nadal (2000) notes that prices for other traditional crops su
ff
ered declines similar to or
greater than that of maize, making a shift to other crops less viable. Pointing to evidence
of expanding cultivation and declining yields in some traditional areas, he attributes the
apparent persistence of traditional production to survival strategies of peasant farmers,
who bring more marginal lands under cultivation in order to grow for subsistence. Yúnez-
Naude and Barceinas Paredes (2003) suggest that a signi
ff
cant proportion of corn farmers
grow for subsistence and are likely to remain isolated from market forces, reducing the
impact of falling prices and the threat to maize genetic diversity. However, Taylor and
Dyer (2003) found that there has indeed been a signi
fi
cant increase in rural migration to
the USA since the mid-1980s, and that trend has been particularly rapid since NAFTA
took e
fi
ect, showing an increase of 175 percent from 1994 to 2002.
It is di
ff
cult to believe that such large-scale migratory trends will not eventually trans-
late into losses in maize production, local knowledge and maize diversity. The threats to
