Corn and Mexican Campesino Farmland Transformation by Dr. Ann López
Scientists speculate that somewhere between 7000 and 12,000 years ago, Mesoamerican farmers created traditional corn by crossbreeding wild grasses. As traditional corn diffused to the south and north, hand-selected seeds from corn plants that thrived locally, led to new strains adapted to different soils, pests, moisture levels and growing seasons. At least 20,000 traditional genetic corn varieties, each adapted to a unique microclimate, developed through this artificial selection process. For thousands of years, these genetically diverse corn varieties have provided the staple food source for small farmers and their families who live geographically dispersed from South America to the Arizona.
The success of Mexico’s pre-Hispanic agriculture can be attributed primarily to the use of multiple-cropping systems or polycultures. Though temperatures vary throughout the year and region, the primary limiting factor is water for irrigation in many geographic areas of Mexico. Most traditional farming systems are temporal or dependent exclusively upon rainfall for irrigation. Planting and harvesting cycles are thus typically timed with the May through October rainy season.
In multiple-crop systems, more than one crop occupies the same piece of land either simultaneously or in some type of rotational sequence during the season (Gliessman 1992). Prior to the Green Revolution introduction of agrochemicals and mechanization into Mexico, polycultures were the ubiquitous means of sustenance for farmers and their families. A common traditional multiple-cropping system that has been extensively studied is the corn, bean and squash polyculture or intercrop. This intercrop is ideally suited for irrigation dependency on seasonal rainfall and for insertion into the cleared tropical scrub vegetation characteristic of the many regions of Mexico.
The intercrop is typically cultivated in ecuaros or guamiles. Ecuaros or guamiles are agroecosystems characteristic of the west central Mexico rocky hillsides. They are cultivated and maintained entirely by hand using pre-Hispanic farming methods. The ubiquitous tropical scrub vegetation is cleared from a cultivation site and the agroecosystem is subsequently imbedded into the surrounding native vegetation.
This unique cropping system has been extensively studied because of the high corn yields that result from this form of agriculture. The intercropping of corn (Zea mays), beans (Phaseolus vulgaris) and squash (Cucurbita sp.) together results in corn yields that are as much as 50% higher than corn planted alone in a monoculture. In spite of a reduction in the overall yields for the beans and squash in the polyculture, the total yield for all three crops is much higher per unit of land planted than when the individual crops are each planted in single-crop systems or monocultures.
Studies have shown that intricate ecological mutualisms among the three crops account for their overall success in a polyculture. In the presence of corn, beans have a stronger tendency to form nitrogen nodules as a result of their exposure to Rhizobium sp. bacteria in the soil. Fixed nitrogen is then made available to corn through mycorrhizal fungi that connect the root systems of the corn and beans. An analysis of soil nitrogen content after the polyculture has been harvested shows that soil nitrogen concentration actually increases (Gliessman 1998). By contrast, in a corn monoculture, soil nitrogen concentrations decline.
The corn plant stalks also provide support for the bean plants. The broad leaves of the squash plants shade the ground and thus inhibit weed growth. In addition potential allelopathic compounds formed on the leaf surfaces are washed into the soil as leachates by rainfall. These compounds are suspected of further inhibiting weed growth (Gliessman 1992). Finally, herbivory is reduced in the corn, bean and squash intercrop because food sources are less concentrated and more difficult to find in the mixture. The architecture of the intercrop provides microclimatic conditions which attract beneficial insects including predatory insects. Beneficial insects are further attracted to the intercrop by the presence of diverse pollen and nectar sources.
The pre-Hispanic corn, bean and squash intercrop also included amaranth. Amaranth (Amaranthus sp.) promoted a reduction in herbivory. Herbivorous insects prefer the leaves of amaranth to those of the corn plant (Gliessman 1997, personal communication). In addition, amaranth appears to be able to withstand the ravages of herbivory more successfully than corn. Amaranth as part of the intercrop is able to divert herbivory away from the more vulnerable corn plants, thereby conserving the corn’s photosynthetic surfaces and promoting elevated yields. After the Conquest the Spanish prohibited the growth and consumption of amaranth because of the grain’s association with indigenous sacrificial rituals.
In some regions of Mexico in which the rainy season extends beyond October, a second legume crop is planted after the corn, bean and squash intercrop is harvested. Typically, a crop of garbanzo beans or a legume that serves as fodder for animals, referred to locally as janamargo, is planted as a monoculture, rotationally on the cleared ground. Both crops have lower water requirements than corn, and are thus successfully dry farmed following the rains. A small amount of these second crops is typically harvested for family and livestock use. However, most farmers sell the majority of the harvest as a source of additional family income.
Prior to the advent of NAFTA, largely due to the thousands of genetic corn strains adapted to multiple ecosystems, Mexico was designated as the world’s corn genetics reservoir. Whenever farmers anywhere in the world had problems with their corn such as an insect infestation, they went to Mexico to locate a genetic strain living in comparable environmental conditions. Often, crossing the afflicted foreign corn with a strain in Mexico resulted in resolution of the problem.
Since the 1940s introduction of “Green Revolution” technology, the Mexican government has promoted agriculture as an instrument of industrialization rather than as a legitimate way of life. In contrast Mexican campesinos continue to experience their farming practices as much more than just a job. In fact, corn farming is a lifestyle in which farming practices, community relationships and family members are integrated into the farming process and the natural environment.
In response to the pressures wrought by NAFTA, corporate penetration, and Green Revolution technology, the farmlands of Mexican countryside are undergoing rapid transformation away from the sustainable foundational polyculture. I argue that the transformation of small subsistence farms away from the agricultural foundational intercrop cultivation in the Mexico countryside was given initial impetus by the historic lack of a coherent government-sponsored agricultural policy that includes small subsistence farmers and the introduction of the Green Revolution homogenized high yielding varieties of corn with their requisite agrochemical inputs for crop production in the 1940s.
In a desperate attempt to generate income for family support, some campesinos are attempting to convert their lands to industrial monoculture corn production, hoping for elevated yields by relinquishing their traditional hand-selected corn strains and adopting the heavily U.S. promoted hybrid seeds with their requisite agrochemicals. Others are converting their intercrop land to pasture for export beef production. Some replace their corn, bean and squash intercrop with export crops of strawberries, broccoli, tomatoes, and cauliflower. Still others leave their land fallow in the care of a relative when they migrate. Some even sell their land under great duress.
As a result of extensive plant breeding leading to highly productive strains of commercial hybrid corn, and U.S. Congress-granted subsidies of billions of dollars to huge U.S. agribusiness operations, the United States is the largest commercial corn producer and exporter in the world. The U.S. corn sector is the largest recipient of U.S. government subsidies, totaling over $13 billion in 2014 for the following 10 years.
With NAFTA’s “free-trade” policies, huge U.S. commercial corn surpluses are being dumped into Mexico where the U.S. Department of Agriculture estimates that imports of corn to Mexico from the U.S. have increased eighteen fold since NAFTA went into effect in 1994. As a result, 50 percent of total corn consumption in Mexico is now commercial corn imported from the United States.
As huge commercial corn shipments from the U.S. continue to invade the Mexican countryside, biotechnology companies are manufacturing, newer, ever more biologically bizarre transgenic corn varieties. Without fully comprehending or testing the potential health and ecological effects of the new strains, the firms are manufacturing, among others, “Terminator” corn strains and corn strains with gene transfers of biological endotoxins functioning as pesticides, such as “Bt corn.” These new endotoxin-bearing seeds were initially advertised as the solution to excessive pesticide use in the U.S., since the plants are designed to eliminate pests by carrying transgenes that destroy herbivorous plant predators. However, a report by the Northwest Science and Environmental Policy Center in 2003 confirmed that the planting of 550 million acres of genetically engineered corn, soybeans and cotton in the United States since 1996 actually increased pesticide use by about 50 million pounds (Pesticide Action Network Alert 2004)!
Many west central Mexico farmers who can afford to purchase the costly “maíz mejorado” (“improved” transgenic corn) seeds, are replacing their traditional maíz criollo corn seed, hand-selected for generations and a unique genetic fit to their land, with genetically homogenized commercial strains from the U.S. Others who cannot afford the costly hybrid seeds have been exhorted by their government to exchange their traditional, genetically diverse, hand-selected seeds for hybrid seeds in the government-sponsored program, kilo por kilo (a kilogram of traditional seed exchanged for a kilogram of hybrid homogenized seed) program.
As agents of industrialization U.S. corporations are well represented in Mexico by a few agribusiness giants. About 75 percent of global cereals, including corn, are controlled by only two multinational companies, Cargill and Archer Daniels Midland (Smaller 2005). These two colossal mega-corporations are the largest corn exporters to Mexico and the primary beneficiaries of corn exports to Mexico. In addition, agribusinesses in Mexico’s rural countryside include Monsanto’s Asgrow and Cargill, DeKalb and Hartz, as well as Dupont’s Pioneer. Company signs are posted alongside roadsides next to commercial hybrid corn fields throughout the countryside, advertising the replacement of traditional corn varieties with the commercial homogenized imported strains.
The loss of genetic diversity with the replacement of traditional corn strains with hybrid and transgenic varieties has progressively narrowed corn’s worldwide genetic reservoir to such an extent that in 1993, 71 percent of the world’s commercial corn crop was derived from only six genetic varieties (Gliessman 1998). The U.S. southern corn leaf blight is an example of the devastation that can occur in monoculture fields of commercialized corn. The blight destroyed 15 percent of the U.S. corn crop, or over 700 million bushels in 1970 (Wolkomir 1995).
The narrowing and genetic distortion of corn stocks ultimately places corn, one of the three grains that support all of humanity, at risk. In Mexico, the foundation for the entire campesino culture is at risk. Angus Wright eloquently asserts “the effect (of the introduction of commercialized hybrid strains) was to eliminate the system of security and stability built into agriculture by thousands of years of peasant technology practiced under widely varying circumstances and adapted to those differing conditions “ (Wright 1990:180). Genetic diversity is the raw material for plant breeding. Loss of diversity may restrict opportunities for future breeding efforts. Genetic diversity is an essential component of environmental resistance and protects the crop from extensive loss from disease, herbivory, or unpredicted variations in environmental conditions. Genetic diversity also promotes crop flexibility with the ability of plants to adapt to changes in seasonal conditions over time (Gliessman 1998).
Genetic erosion creates genetic vulnerability whereby genetically uniform plant varieties become susceptible to pest and disease epidemics, or to losses caused by extremes in the weather. Genetically uniform crops provide the ideal conditions for the rapid outbreak of pests and plant diseases. Pests and diseases in turn, have the capacity to undergo rapid genetic change, potentially quickly adapting to changes in their hosts’ defenses (Gliessman 1998). Biologically, the replacement of traditional corn varieties artificially selected by subsistence farmers for thousands of years, with commercially produced, hybrid, high-yielding varieties (HYVs) and/or genetically bioengineered varieties, is tantamount to the potential mass extinction of corn’s genetic reservoir produced over at least 7,000 years! The fear is that carelessness, ignorance and greed could wipe out what nature and Mexican farmers spent thousands of years developing-a food crop inseparable from the history, environment, culture and cooking of Mexico.
In spite of the widespread commercialization of hybrid and transgenic corn strains in the Mexican countryside, Mexican federal district judges in 2013 and 2014 placed an indefinite ban on the commercial growth of genetically engineered corn and soybeans; citing that transgenic corn posed “the risk of imminent harm to the environment.” However, corn is wind pollinated, so that widespread contamination of traditional corn strains has already occurred over the past twenty years of NAFTA. Additionally, without DNA testing, it will be very difficult to determine which fields are transgenic and which harbor traditional corn genetics, by observation alone. However, the ban will allow small producer and subsistence farmers still living in the countryside to possibly regroup and move in the direction of recreating their environmentally sustainable polycultures.
The impact of NAFTA in 1994 with its abrupt removal of government price supports for corn; leading to mass migration out of the countryside, along with the overturning of Article 27 of the Mexican Constitution and resultant land sales and rentals, further promoted the transition away from traditional intercrop cultivation. The accelerated disruption of the agricultural campesino intercrop cultural cornerstone and the ensuing farm transformations have ultimately served to promote the separation of campesinos and their family members from the sustainable, productive agroecological immersion in the countryside that was once a cultural norm. A disrupted connection with the natural world has, in turn, given rise to the massive social transformations and emigration out of the countryside clearly evident in the Mexican countryside today.
As cultural disintegration and death slip through the countryside, disrupting one farm and family after another, transnational corporations are enjoying an economic boom. Spurred by NAFTA, their profits are soaring. I argue that while the United States spends billions of taxpayer dollars unsuccessfully attempting to stem the tidal flow of illegal drugs from Mexico, predominantly U.S-originating transnational corporations are exporting and aggressively promoting deadly environmental, health, and culture destroying drugs, chemicals and agricultural products to Mexico with impunity. As purveyors of addiction and even genetic and human death, their hybrid and bioengineered seeds, agrochemicals, caffeine, and nicotine products exacerbate the already compromised health of an impoverished under and malnourished rural population in Mexico. Primed by the authoritarian institutional mechanisms in place in the rural countryside, largely uneducated rural campesinos are easy corporate prey. The price of succumbing to the lure of corporate wares is high. Campesinos ultimately risk their health, lives, and even the traditional corn foundation of their culture. This damaging and deadly transnational corporate contribution constitutes the United States’ shameful legacy in the Mexican countryside.