Traditional vs. Industrial Agricultural Production of Maize in Mexico
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| Photo Credit: Michel Wattiaux |
Scenario | Abstract | Introduction | Historical Context | Methods | Results | Analysis | Conclusion | About the Authors | Citations
The Food and Agriculture Organization (FAO) of the United Nations has formed a committee to research the sustainability of peasant subsistence farming systems in response to climate change predictions. They have chosen to begin this investigation with a case study of Mexican maize or corn production as an example of a system where peasant subsistence and green revolution production is practiced. The goal of this committee is to determine which agricultural system shows the most adaptability to climate change in central Mexico and then provide recommendations to teams consisting of policymakers, experts, and communities.
Maize or corn is a staple on Mexican tables and fields. A significant peasant population in Mexico’s Central Highlands relies upon maize production for subsistence and/or income, but climatic changes like higher temperatures, lower rainfall, and increased variability threaten this integral part of the Mexican agricultural landscape. In this analysis, we apply a policy adaptation framework to assess the relative adaptability of peasant subsistence milpa systems and the more modern systems produced by implementation of green revolution technologies in Mexico. We conclude that many of the adaptation options for green revolution-style systems are too costly or difficult to access for many small, isolated farmers and that diversification and selective use of Mexico’s wealth of native maize landraces to better suit drought and other climate change conditions provide effective and accessible mitigation of climate change pressures for peasant subsistence farmers. However, private and public programs could make several of the other adaptations we outline in this study more feasible for subsistence and commodity growers alike.
Maize or corn is central to the Mexican diet and culture. Maize was domesticated in the balsas river basin in southwestern Mexico approximately 10,000 years ago (Hufford et al. 2012). Through pre Colombian times, the colonial era, and the twentieth century, maize consumption has remained a key source of nutrition in the Mexican diet. Mexicans consume 267 grams of maize per person per day, that’s the third highest consumption of maize in the world only falling behind Lesotho and Malawi (Ranum et al. 2014). Additionally, the CIA World Factbook lists corn as Mexico’s most important agricultural product (2014).
Maize is a difficult crop to grow, however. It demands high inputs of nutrients and water and a long growing season to fully ripen the crop. Erratic climate events have begun to threaten maize production in recent years – July frosts and extended droughts cause low yields and crop failure (Halle Eakin 2005). These unusual climate events are linked to climate change, which may worsen in severity or frequency as climate change progresses (The World Bank Group 2015). Because corn is such an integral part of the Mexican diet, yet is becoming increasingly more difficult to produce, our research committee seeks to investigate which maize production systems are most effective at managing climate risk. We will use an adaptation policy framework to assess our research question: what are feasible adaptation strategies for peasant subsistence and green revolution-style maize producers that allow them to adequately address the risks of climate change?
Agriculture has been practiced in the Americas and Mexico for thousands of years. Indigenous populations built thriving civilizations based upon agriculture and the environmental strain incurred occasionally led to their destruction (Diamond 2011). After contact with Europeans, cultivation was shifted to crops of the European taste such as wheat, sugarcane, tobacco, and cotton (Whitmore & Turner II 1992). The green revolution transformed agriculture around the globe from the 1940s through the 1960s with the implementation of input based agricultural techniques. Since the 1990s, oeoliberal policies have had a major impact on maize farming communities leading to a loss of subsistence farming and increased out-migration. All of these data point towards potential challenges modern smallholder and peasant producers will face due to climate change, namely a lack of irrigation infrastructure and a dearth of both farm labor and mechanical substitutes.
Agricultural Practices in Mexico
| 10,000 BC to 1500 AD | ||||||||
| Milpa: Polyculture Technique | Chinampas: Raised-bed in Wetlands | Terracing: Planting on Slopes of Mountains | ||||||
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| 1500 to 1950 | ||||||||
| Plowing with Animals | Growing Cash Crops such as Wheat | |||||||
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| 1950 to the Present | ||||||||
| Industrialization | Rural Out-Migration | |||||||
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- Definitions
- Cases
- Adaptation Policy Framework
Central to the methodology of our study was first defining some key terms that will be used in the analysis of our cases. We first identified the goals of “adaptability” by considering the central components of sustainability and resilience.
| Sustainability | The likelihood an existing system of resource use will persist indefinitely without a decline in the resource base or in the social welfare it delivers (Walker and Salt 2006). |
| Resiliency | The amount of change a system can undergo (its capacity to absorb disturbance) and remain within the same regime -- essentially retaining the same function, structure, and feed backs (Walker & Salt 2006). |
| Adaptability | The capacity of actors in a system (people) to manage resilience (Walker and Salt 2006). |
A robust survey of previous literature led us to elect and precisely define our two case populations as peasant subsistence and green revolution agriculture. Our definitions relied heavily upon an assimilation of the various definitions of traditional milpa in the literature (See Table 1 below) and upon the survey data from Arnés et al. (2013) and Eakin et al. (2014) for a definition of modern commercial farming practices.
Table 1. Definitions of Traditional Agriculture Found in the Literature| Source | Definition of “Traditional” Agriculture |
| Dendoovena et al. 2012 | “Traditional and widely used cultivation techniques consist in monoculture of often traditional maize varieties, low N fertilizer application rates, no or little irrigation, removal of crop residue for animal feed or fuel, and little or no use of herbicides and pesticides. This tillage based cultivation technique has resulted in degraded unstructured soil prone to wind and water erosion with low organic matter and nutrient content (Govaerts et al., 2008).” |
| Crews 1993 | “Many traditional farmers in central and northern Mexico rely on alfalfa (Medicago sativa, L.) as the primary nitrogen source for their maize crops. . . In many traditional Mexican agro ecosystems, including those discussed in this study, alfalfa plots are cut 6-10 times per year, and the fodder is fed to work and dairy animals. Manure from these animals is collected, stored, and applied to the maize fields either before planting or as a side dress. In this way a portion of the nitrogen fixed by the alfalfa is made available to the maize. In addition, after 3-5 years, the farmers plow a given alfalfa plot under and sow maize.” |
| Silva et al. 2003 | “The milpa system is a prehispanic cultivation method, in which beans are intercropped with maize and squash, together with diverse other plant species that are locally used for medicinal and nutritional purposes (47). This cultural practice promotes bean nitrogen fixation, and its advantages have been recognized (5, 29).” |
| Arslan 2011 | Discussed higher use of traditional maize varieties and seed saving among Mexican subsistence farmers than commercial sellers. Concludes that 46% of subsistence farmers use exclusively seed they have grown and saved. |
| Brush, Tadesse, and Dusen 2003 | “The ‘classic’ Mesoamerican farming system is referred to as milpa – defined as a field that is intercropped with three principal species (Zea mays, Phaseolus spp. and Cucurbita spp.), often with minor species (e.g. Capsicum spp., Lycoperscion esculentum), and in which edible leafy weeds – quelites (e.g., Amaranthus spp.) – are tolerated and harvested.” |
| Mullaney 2014 | “In terms of production, maize was first domesticated in Mexico’s central highlands more than 7,000 years ago and currently occupies half of the country’s cropland, two thirds of which is cultivated by small-scale farmers without irrigation . . . and based on locally adapted, farmer-bred criollo varieties.” |
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| http://commons.wikimedia.org/wiki/File:Milpa_in_Quiche_Guatemala.JPG |
From this information we operationalized peasant subsistence and green revolution agriculture. Peasant subsistence systems refer to small farms with diverse intercropping production, largely hand and animal labor, and a reliance on traditional seed stock (“landraces”). The green revolution technology, on the other hand, relies upon genetically engineered (GE) and hybrid seed varieties, mechanized labor, applications of synthetic inputs of pesticides, herbicides, and fertilizers, and monoculture systems that grow only maize. For complete side by side definitions of these agricultural systems see the list below ("Characteristics of different farming systems").
Table 2. Characteristics of Different Farming Systems| Peasant Subsistence Agriculture | Green Revolution Agriculture | |
| Source of Labor | Animal plowing and sometimes weed control with manual sowing and harvesting | Mechanized sowing (mechanical seed drill) and manual or mechanized harvesting |
| Source of Seed | Mixtures of traditional, saved seed varieties and purchased varieties | Purchased high-yield seeds of hybrid and genetically engineered varieties |
| Number of Crops | Intercropping of Maize and Squash and sometimes beans | Fields are planted solely with corn |
| Crop Rotation | Rotations with legumes for animal forage (alfalfa, vetch) or human consumption (beans, peas) | No rotation or fallow time |
| Fertilizer | Some synthetic nitrogen application, cropping in rotation with legumes, application of animal manures | Synthetic nitrogen application |
| Weed Control | Some weeds tolerated, animal plowing used to mound dirt around stalks | Synthetic herbicide application |
| Insect/ Wildlife Control | Squash on corn deters animals, no insect control | Synthetic pesticide application |
| Water Source | Rain- Fed | Irrigation |
Our analysis of the adaptability, resiliency, and sustainability of maize production in Mexico was based off of a literature review that focused on stakeholder opinion. It primarily incorporates a “priority-setting methodology” (Lee, et. al 2014) based on an “adaptation policy framework” (Conde et. al 2006). The steps include reviewing climate change’s impact on agriculture,identifying response options, prioritizing these options, and developing country-specific action plans (Lee, et. al 2014). The last step will be modified to develop region-specific plans, taking into consideration the different resources maize farmers have access to.
- Identification of Climate Pressures and their Affect on Agriculture
- Identifying Response Options
- Prioritizing options based on cost, amount of time required, and availability of technology or other inputs (Lee, et. al)
Overall, if climate change is not mitigated it is expected to result in a 10% decrease in “caloric availability by 2050” in developing countries (Fan, et. al 2012). Additionally, according to Mercer et. al (2012), global maize production fell 3.8% between 1980 and 2010.
Table 3. Climate Pressures and Agricultural Responses| Climate Pressures | Expected Agricultural Response |
| Drought | Decrease in Production |
| Higher Temperatures | Increased Fragility |
| Climate Variability | Increased Fragility |
| Extreme Events | Damaged Crops |
This task is designed for stakeholders (smallholder farmers) to be involved in the process that will ultimately determine the future of their livelihoods.
Table 4. Response Options| Adaptation strategies for Peasant Subsistence | Adaptation Strategies for Green Revolution | ||||||
| Temperature Increase/Heat Stress | Utilization of local landrace varieties that mature rapidly or are particularly suited to arid conditions (Mercer 2012; Conde and Eakin 2003) |
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| Frost Increase/ Decrease | Use of seasonal climate forecasts for decision making (Conde and Eakin 2003) |
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| Precipitation Decrease |
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| Extreme Events Increase | Crop and Animal Diversification (Altieri 2008; Conde and Eakin 2003) | This provides other income streams for farmers and can provide benefits in the form of green manure or actual manure for application to maize fields. |
Table 5. Summary of Peasant Subsistence Prioritization Analysis
| Economic Costs | Time Required | Accessibility | |
| Agroforestry | Low | High (10+ years) | Information may be accessible at community level, if not availability decreases dramatically |
| Crop and Animal Diversity | Varies depending upon any new infrastructure for planting or fencing and shelter for livestock | Low | Very accessible |
| Utilization of local landrace varieties that mature rapidly or are particularly suited to arid conditions | Low | Low | Very accessible |
| Use of seasonal climate forecasts for decision making | Low | Low | Information not readily available for isolated communities and uneducated farmers, lack of extension services |
| Irrigation | High | Low | Moderately accessible depending on community location and transport to local co-ops or city centers for required materials |
Table 6. Summary of Green Revolution Prioritization Analysis
| Economic Costs | Time | Accessibility | |
| Drought Resistant GE Seed Varieties | High | Low | Moderately accessible depending on community location and transport to obtain required materials |
| No-Till or low-till Cultivation | High (equipment costs) | Low | Moderately accessible depending on community location and transport to obtain required materials |
| No-Till or low-till Cultivation | High (equipment costs) | Low | Moderately accessible depending on community location and transport to obtain required materials |
| Use of season forecasts to determine crops and planting schedules | Low | Low | Information not readily available for isolated communities and uneducated farmers, lack of extension services |
| Precisely apply inputs to encourage maximum production | Varied depending on costs of technology used to calculate and apply inputs | Low | Information not readily available for isolated communities and uneducated farmers, lack of extension services, Moderately accessible depending on community location and transport to obtain required materials |
| Implement crop rotations or fallow periods for maize fields | Moderate (costs of additional equipment required) | Moderate (several years to see benefits of rotation) | Moderately accessible depending on community location and transport to obtain required materials, information availability from extension or crop consultant services is also a factor |
| Diversify into other crops or animal husbandry | Varies depending upon any new infrastructure for planting or fencing and shelter for livestock | Low | Moderately accessible depending on community location and transport to obtain required materials, low information availability from extension, possible paid use of crop consultant |
The analysis of the five adaptation strategies for the peasant subsistence systems revealed that production diversification and use of local landraces were the most feasible options. The analysis of the six adaptation strategies for green revolution farmers revealed that crop and fallow rotations and production diversification are the most feasible strategies. These conclusions are remarkably similar to those of the peasant analysis – indicating that diversification of crops and crop varieties is universally useful for adaption to climate change and that both groups face similar barriers to adoption. Our analysis essentially concluded that the same adaptation strategies were useful for both groups and farmers with more access to capital could adopt further strategies. Addressing the question of which system is “more” adaptable, it is of note that based upon studies already conducted in the literature, peasant subsistence systems may be more ecologically resilient before any adaptation strategy is implemented. In summary, our conclusions are that agro-ecosystems managed in the peasant method are likely more resilient than the high-input commercial model, but that the same human interventions to adapt can benefit both systems.
Based upon the political and economic conditions we explained earlier in this paper such as NAFTA and neoliberal reforms, we have thus turned our attention to suggestions for improving the availability of technologies that we concluded were not feasible in this study. First, programs should be implemented to encourage farmers to coordinate with communities, researchers, and local organizations to encourage crop diversity, focusing on the resiliency of crops in regards to climate change. Local and national governments should work together to protect farmers from the market by re-introducing subsidies and crop insurance for subsistence farmers, revitalizing information systems like extension, and creating incentives that would encourage planting a diversity of crops. Finally, other nations should re-assess the long-term impacts of agreements like NAFTA on subsistence farmers, and explore alternative policy structures that could mitigate the worst effects.
Through the use of a modified policy adaptation framework, we have investigated the possible adaptation strategies for peasant subsistence and green revolution maize farmers to protect their livelihoods. Our analysis determined that without serious policy changes to improve the availability of information, crop insurance, and new agronomy technologies, many of the adaptation strategies associated with the green revolution-style systems were untenable in the context of isolated peasant farmers. Such policy changes would also improve the accessibility of the adaptation strategies we outlined in the peasant subsistence adaptation analysis. In our analysis of the peasant subsistence system, we concluded that crop diversification and use of appropriate local landraces provided the most promise as adaptation strategies for his poorer group of farmers. For green revolution farmers we similarly concluded that crop diversification and rotation were the least costly and most accessible to implement. Our results indicate that peasant subsistence systems may be more naturally resilient in and of themselves, but both agricultural models can adapt to climate change through diversification at relatively low costs. A central weakness of this study is that we were unable to locate robust data collected from stakeholders currently practicing more modern, green revolution cropping techniques. This line of inquiry provides fertile ground for further research projects.
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| http://en.wikipedia.org/wiki/User:Rsilva08/Maize_in_Maya_Culture |
| Alisha Bower | Alisha is a masters student in the La Follette School of Public Affairs. Her specialties lie in nonprofit management and food systems analysis, with a pet interest in Latin American policy and politics. When she’s not studying she enjoys knitting, brewing craft beer, singing loudly while performing house chores, and helping out on her father’s grass-fed beef farm. |
| Julia Prieto | Julia is a junior majoring in Community and Environmental Sociology at UW-Madison. Her interests lie in water rights, environmental governance, and restoration ecology. She hopes to attend the University of Freiburg to obtain a Master's in Environmental Governance and eventually work for the United Nations Environment Programme. Apart from studying, Julia is an avid horseback rider, enjoys hiking with her dog, and loves to try new recipes in the kitchen. |
| Soo Kim | Soo is a third year undergraduate student studying plant pathology. She hopes to go into alternative medicine after her undergraduate years. She loves to travel to new countries and loves to learn new instruments during her free time. . |
Adie, RF. 1975. “Land and Politics in Mexico.” Canadian Journal of Political Science / Revue Canadienne de Science Politique 8 (2): 299–305.
Alix-Garcia, J. 2011. “The Sources and Evolution of Inequality in Mexican Ejidos.” Investigación Económica 70 (278): 101–28.
Altieri, MA. 2008. “Scaling up Agroecological Approaches for Food Sovereignty in Latin America.” Soc. for Int. Dev. 51 (4): 472–80.
2014.Strengthening Resilience of Modern Farming Systems: A Key Prerequisite for Sustainable Agricultural Production in an Era of Climate Change. Third World Network.
Anwar, MR, DL Liu, I Macadam, and G Kelly. 2012. “Adapting Agriculture to Climate Change: A Review.” Theor. and Appl. Clim. 113 (1-2): 225–45.
Arnés, E, J Antonio, E del Val, and M Astier. 2013. “Sustainability and Climate Variability in Low-Input Peasant Maize Systems in the Central Mexican Highlands.” Agric., Ecosyst. & Environ. 181 (December): 195–205.
Arslan, A. 2011. “Shadow vs. Market Prices in Explaining Land Allocation: Subsistence Maize Cultivation in Rural Mexico.” Food Policy36 (5): 606–14.
Brush, SB, D Tadesse, and EV Dusen. 2003. “Crop Diversity in Peasant and IndustrializedAgriculture: Mexico and California.” Soc. & Nat. Resour. 16 (2): 123–41.
Butzer, KW. 1992a. “The Americas before and after 1492: An Introduction to Current Geographical Research.” Annals of the Assoc. of American Geogr. 82 (3): 345–68.
1992b. “Spanish Conquest Society in the New World: Ecological Readaptation and Cultural Transformation.” In Person, Place and Thing: Interpretive and Empirical Essays in Cultural Geography, edited by ST Wong, 2nd edition. Baton Rouge, LA: Louisiana State Univ.
Campos, M, A Velázquez, and M McCall. 2014. “Adaptation Strategies to Climatic Variability: A Case Study of Small-Scale Farmers in Rural Mexico.” Land Use Policy 38 (May): 533–40.
Casey, JF. 2004. “Agroforestry Adoption in Mexico: Using Keynes to Better Understand Farmer Decision-Making.” J. of Post Keynes. Econ.26 (3): 505–21.
Chevalier, F. 1963. Land and Society in Colonial Mexico: The Great Hacienda. Berkeley: University of California Press.
CIA. 2014. “Mexico”. The CIA World Factbook. June 20.https://www.cia.gov/library/publications/the-world-factbook/geos/mx.html.
Cleveland, DA, and D Soleri. 2005. “Rethinking the Risk Management Process for Genetically Engineered Crop Varieties in Small-Scale, Traditionally Based Agriculture.” Ecol. and Soc. 10 (1): 9.
Conde, C, and H Eakin. 2003. “Adaptation to Climate Variability and Change in Tlaxcala, Mexico.” In Climate Change, Adaptive Capacity and Development, edited by JB Smith, RJT Klein, and S Huq, 241–59. London: Imperial College Press.
Conde, C, R Ferrer, and S Orozco. 2006. “Climate Change and Climate Variability Impacts on Rainfed Agricultural Activities and Possible Adaptation Measures. A Mexican Case Study.” Atmósfera 19 (3): 181–94.
Connor, JD, K Schwabe, D King, and K Knapp. 2012. “Irrigated Agriculture and Climate Change: The Influence of Water Supply Variability and Salinity on Adaptation.” Ecological Economics 77 (May): 149–57.
Cook, SF, and WW Borah. 1979. Essays in Population History: Mexico and California. Vol. 3. Berkeley, Calif: University of California Press.
Crews, TE. 1993. “Phosphorus Regulation of Nitrogen Fixation in a Traditional Mexican Agroecosystem.” Biogeochemistry 21 (3): 141–66.
Dendoovena, L, VF Gutiérrez-Olivab, L Patiño-Zúñigaa, DA Ramírez-Villanuevac, N Verhulstd, M Luna-Guidoa, R Marscha, et al. 2012. “Greenhouse Gas Emissions Under Conservation Agriculture Compared to Traditional Cultivation of Maize in the Central Highlands of Mexico.” Sci. of the Total Environ. 431 (August): 237–44.
Denevan, WM. 1970. “Aboriginal Drained-Field Cultivation in the Americas.” Sci., New Series, 169 (3946): 647–54.
Diamond, J. 2011. Collapse: How Societies Choose to Fail or Succeed: Revised Edition. Revised edition. New York: Penguin Books.
Eakin, H. 2005. “Institutional Change, Climate Risk, and Rural Vulnerability: Cases from Central Mexico.” Elsevier Ltd. 33 (11): 1923–38.
Eakin, H, H Perales, K Appendini, and S Sweeney. 2014. “Selling Maize in Mexico: The Persistence of Peasant Farming in an Era of Global Markets.” Dev. and Change 45 (1): 133–55.
FAO. 2015. “Mexico.”FAOSTAT. http://faostat.fao.org/CountryProfiles/Country_Profile/Direct.aspx?lang=en&area=138.
Finlay, KJ, and JE Luck. 2011. “Response of the Bird Cherry-Oat Aphid (Rhopalosiphum Padi) to Climate Change in Relation to Its Pest Status, Vectoring Potential and Function in a Crop–vector–virus Pathosystem.” Agric., Ecosyst. & Environ. 144 (1): 405–21.
de Frece, A, and N Poole. 2008. “Constructing Livelihoods in Rural Mexico: Milpa in Mayan Culture.” The J. of Peasant Stud. 35 (2): 335–52.
Gliessman, SR, E Engles, and R Krieger. 1998.Agroecology: Ecological Processes in Sustainable Agriculture. Chelsea, MI: Ann Arbor Press.
Harwood, J. 2009. “Peasant Friendly Plant Breeding and the Early Years of the Green Revolution in Mexico.” Agric. Hist. 83 (3): 384–410.
Hillel, D. 1991. Out of the Earth: Civilization and the Life of the Soil. New York : Toronto : New York: Free Press ; Collier Macmillan Canada ; Maxwell Macmillan International.
Howden, SM, JF Soussana, FN Tubiello, N Chhetri, M Dunlop, and H Meinke. 2007. “Adapting Agriculture to Climate Change.” Proc. of the Natl. Acad. of Sci. 104 (50): 19691–96.
Hufford, MB, X Xu, J van Heerwaarden, T Pyhäjärvi, JM Chia, RA Cartwright, RJ Elshire, et al. 2012. “Comparative Population Genomics of Maize Domestication and Improvement.” Nat. Genet. 44 (7): 808–11.
Hunter, RW. 2009. People, Sheep, and Landscape Change in Colonial Mexico the Sixteenth-Century Transformation of the Valle Del Mezquital. Baton Rouge, La.: Louisiana State University.
INEGI. 2007. “Censo Agrícola, Ganadero Y Forestal 2007.” INEGI: Instituto Nacional de Estadística Y Geographía. Lin, BB. 2011. “Resilience in Agriculture through Crop Diversification: Adaptive Management for Environmental Change.”BioScience 61 (3): 183–93.
MacLachlan, Colin M., and Jaime E. Rodríguez O. 1980. The Forging of the Cosmic Race: A Reinterpretation of Colonial Mexico. Berkeley: University of California Press.
Melville, EGK. 1997. A Plague of Sheep: Environmental Consequences of the Conquest of Mexico. Studies in Environment and History. Cambridge [England] ; New York, NY, USA: Cambridge University Press.
Mercer, KL, HR Perales, and JD Wainwright. 2012. “Climate Change and the Transgenic Adaptation Strategy: Smallholder Livelihoods, Climate Justice, and Maize Landraces in Mexico.”Glob. Environ. Change22: 495–504.
Mullaney, EG. 2014. “Geopolitical Maize: Peasant Seeds, Everyday Practices, and Food Security in Mexico.”Geopolit. 19 (2): 406–30.
Ranum, P, JP Peña-Rosas, and MN Garcia-Casal. 2014. “Global Maize Production, Utilization, and Consumption.”Annals of the New York Acad. of Sci. 1312 (1): 105–12.
Silva, C, P Vinuesa, LE Eguiarte, E Martínez-Romero, and V Souza. 2003. “Rhizobium Etli and Rhizobium Gallicum Nodulate Common Bean (Phaseolus Vulgaris) in a Traditionally Managed Milpa Plot in Mexico: Population Genetics and Biogeographic Implications.” Appl. and Environ. Microbiol. 69 (2): 884–93.
Sonnenfeld, DA. 1992. “Mexico’s ‘Green Revolution,’ 1940-1980: Towards an Environmental History.”Environ. Hist. Rev. 16 (4): 29–52.
The World Bank. 2015. “Mexico.” World DataBank: World Development Indicators.
The World Bank Group. 2015. “Climate Change Knowledge Portal For Development Practitioners and Policy Makers.” Climate Change Knowledge Portal For Development Practitioners and Policy Makers.
Walker, BH, and D Salt. 2006.Resilience Thinking: Sustaining Ecosystems and People in a Changing World. Washington: Island Press.
Wehbe, M, H Eakin, R Seiler, M Vinocur, C Ávila, C Maurutto, and G Sánchez Torres. 2007. “Local Perspectives on Adaptation to Climate Change: Lessons from Mexico and Argentina.” InClimate Change and Adaptation, edited by N Leary, J Adejuwon, V Barros, I Burton, J Kulkarni, and R Lasco, 315–31. London: Earthscan.
Whitmore, TM, and BL Turner II. 1992. “Landscapes of Cultivation in Mesoamerica on the Eve of the Conquest.” Annals of the Assoc. of American Geogr. 82 (3): 402–25.