From Crops to Concrete: Urbanization, Deagriculturalization, and Construction Material Mining in Central Mexico

Abstract

In tropical countries, urbanization and rural deagriculturalization are intimately linked processes. Growth of the construction industry, which draws labor and materials from rural and periurban areas, is a key component of rural–urban interactions. Using a case study from the Perote Valley, Mexico, this article analyzes how urban-driven concrete aggregate mining affects rural agricultural lands and livelihoods. Land-cover changes associated with aggregate surface mining were examined by comparing aerial photographs, satellite images, and Global Positioning System field maps of the valley. In addition, sixty-six formal household interviews were conducted in three agrarian communities. Results indicate that between 1995 and 2006, mine surface area quadrupled, from 181 to 706 hectares, and the spatial distribution of surface mines followed a predictable pattern of extraction, from most to least accessible. Numerous factors persuaded farmers to convert fields to mines, including increased prices for aggregates, consumerist desires for new homes, and declining returns to agriculture. Moreover, farmers believed they could or would recultivate mined land following extraction. Yet, in 2006, among the three agrarian communities, 202 (45 percent) of the 482 hectares of agricultural land extracted were not recultivated. Although deep mines were more likely to be abandoned, findings suggest that land revalorization occurred among farmers, with the scarcity value of nonrenewable aggregates gradually surpassing the land's agricultural value. In the long term, diminished agricultural potential resulting from widespread mine abandonment might drive farmers to migrate to cities for employment, creating a positive feedback between urban demand for construction aggregates and mining of agricultural fields.

En los países tropicales, la urbanización y desagriculturización rural son procesos íntimamente ligados. El crecimiento de la industria de la construcción, que atrae la mano de obra y materiales de las zonas rurales y periurbanas es un componente clave de las interacciones urbano-rurales. Usando un estudio del caso del Valle de Perote, México, este artículo analiza cómo la minería de agregados de construcción, impulsada por la urbanización, afecta a las tierras agrícolas rurales y los medios de subsistencia. Los cambios de la cobertura de la tierra asociados con la minería de agregados a cielo abierto, fueron analizados mediante la comparación de fotografías aéreas, imágenes satelitales y mapas de campo del valle levantados con el Sistema Global de Posicionamiento. Además, se llevaron a cabo sesenta y seis entrevistas formales en los hogares de tres comunidades agrarias. Los resultados indican que entre 1995 y 2006, la superficie minera se cuadruplicó, de 181 a 706 hectáreas, y la distribución espacial de minas a cielo abierto siguió un patrón predecible de extracción, de mayor a menor accesibilidad. Numerosos factores convencieron a los agricultores a convertir los campos a minas, incluyendo el aumento de los precios de los agregados, deseos consumistas de nuevos hogares, y rendimientos decrecientes en la agricultura. Es más, los agricultores creían que podrían volver a cultivar en la tierra de la mina después de la extracción. Sin embargo, en el 2006 de las tres comunidades agrarias, 202 (45 por ciento) de las 482 hectáreas de tierras agrícolas extraídas no fueron cultivadas nuevamente. A pesar de que las minas profundas eran más propensas a ser abandonadas, los hallazgos sugieren que la revalorización de la tierra se produjo entre los agricultores, con el escaso valor de los agregados no renovables superando poco a poco el valor agrícola de la tierra. A largo plazo, el potencial agrícola disminuido producto del abandono generalizado de minas podría impulsar a los agricultores a emigrar a las ciudades en busca de empleo, creando una positiva retroalimentación entre la demanda urbana por agregados de construcción y la minería en campos agrícolas.

Key Words:

• construction aggregate mining
• deagrarianization
• land-use change
• livelihoods
• rural–urban interactions

关键词:

• 建筑总采矿
• 去农业化
• 土地利用的变化
• 生计
• 城乡互动

Palabras clave:

• minería de agregados de construcción
• desagrarización
• cambios de uso del suelo
• medios de subsistencia
• interacciones urbano-rurales

Acknowledgments

I am grateful to the residents of Sierra de Agua, Los Molinos, and Cruz Blanca for their hospitality and assistance; to Alexandra Ponette-González for her time and insightful comments; and to Gil Ortiz, Raul Cortez, Andres de la Rosa, and Sergio Rodríguez for assistance. I thank Bill Doolittle for advising me on portions of this research. I also thank four anonymous reviewers and Karl Zimmerer for their constructive comments. This study was carried out with support from the National Science Foundation Doctoral Dissertation Improvement Grant #0703460 and the Robert E. Veselka Endowed Fellowship Research Grant from the University of Texas at Austin, Department of Geography and the Environment. A shorter version of this article was presented at the 2010 annual meetings of the Association of American Geographers, Washington, DC.

Notes

1. Although Programa de Apoyo Directo al Campo/Program for Direct Assistance in Agriculture (PROCAMPO) was established to support farmers in the interim. PROCAMPO involved monetary payments based on cultivated area (ha) of major subsistence crops; it expired in 2010 (see Klepeis and Vance 2003).

2. In addition to the state's mining permits, each study ejido has particular guidelines and fees for exploiting tepetzil, including a 5 to 10 percent fee on the sale price of the tepetzil, a fee for each front-end loader in operation at the mine, fees for impacts on neighboring plots (e.g., from road and mine dust), and a monthly fee paid while the tepetzil is extracted. Although these guidelines are in place, they are hard to enforce.