Mexican produce agriculture and land degradation: A study of soil salinization in the Mexicali Valley, Mexico.

摘要

The degradation of irrigated lands through the process of soil salinization, the buildup of salts in the soil, has hampered increases in agricultural productivity and threatens the sustainability of large-scale cultivation in critical agricultural regions of the world. It is estimated that a significant portion of the agricultural land in the lower Colorado River basin is afflicted with varying degrees of soil salinization and insufficient attention has been given to the human-environment relationship driving this form of land degradation. Recognized as a critical agricultural region, the Mexicali Valley of Baja California, Mexico cultivates a significant portion of North America's fresh winter produce, with a particular focus on green onions. The spatial distribution of soil salinity is mapped using remotely sensed imagery and its proximate causes and distal drivers are explored using a mixed methods approach, linking macro-scale institutional and economic influences to micro-scale farmer decision-making and environmental conditions. Surface soil salinity is found at levels sufficient to threaten productivity, with a clustered pattern of occurrence that supports the contention for human-induced soil salinity linked to irrigated agriculture. Land-tenure practices, scarce economic investments in agriculture, institutional failure to address soil salinization, and a growing global demand for produce account for the degradation witnessed. This research contributes to the global sustainability effort by clarifying the human-environment relationship resulting in salinity driven land degradation afflicting irrigated agriculture and endangering our global environment.