Investigators
Pamela A. Matson (Principal Investigator) - Stanford University
Rosamond L. Naylor - Stanford University
Walter P. Falcon - Stanford University
Robert B. Dunbar - Professor of Geological and Environmental Sciences and FSI Senior Fellow by courtesy at Stanford University
Steven Gorelick
Jeffrey Koseff
Ivan Ortiz-Monasterio
Stephen Monismith
Carlos Valdes
Peter Vitousek - Stanford University

The Yaqui Valley, in Sonora, Mexico is a region of rapid demographic, economic, and ecological change in both upland and coastal areas. Situated on the west coast of mainland Mexico on the Gulf of California, the Valley currently comprises 225,000 has of irrigated wheat-based agriculture: recently adding aquaculture to its landscape. It is the birthplace of the Green Revolution for wheat and one of Mexico's most productive breadbaskets. Today, population growth, urbanization, agricultural intensification, land use change, water diversions, groundwater pumping, coastal modifications, wetland conversions, and aquaculture growth threaten the sustainability of certain of the region's resources. Research in the Valley has become timely and critical, both in the Valley's own right, and because it is a likely forerunner to similar irrigated valleys around the world.

CESP began research in the Valley in 1992 when Stanford Professors Pamela Matson and Rosamond Naylor teamed up with Dr. Ivan Ortiz-Monasterio of the International Maize and Wheat Improvement Center (CIMMYT) to initiate a study of fertilizer use in intensive wheat-based agriculture. Results of this study indicated that farmers used more fertilizer than required, and excess fertilizer N was lost in the atmosphere in the form of trace gases that cause air pollution and to water systems where it is carried to the Gulf. The researchers evaluated a number of alternative fertilizer management options, and found that farmers could save money by using less fertilizer and still receive comparable yields from their crops.

Since this initial study, Stanford's research presence within the Valley has expanded to include different dimensions of agriculture and variability, the role of institutions and impact of national and international policies, water resource use and management, aquaculture development, the affect on estuaries of upland land use change, and the burgeoning role of the livestock sector. With the recent introduction of shrimp farming, researchers have looked at the dynamics of land use change along the southern Sonora coast and environmental, social and economic impacts of aquaculture.

In the agricultural sector, researchers have used a combination of historical remotely sensed data, ground-based data, modeling and field surveys to evaluate the causes and consequences of agricultural intensification and to analyze the links between agriculture policy and productivity. Economists and water resource specialists have examined the links between water management decisions, crop yields and economic impacts on groundwater use through modeling and economic analysis.

Ongoing research, primarily funded by the Packard Foundation, includes studies of nitrogen fertilizer use; nitrogen transport and nitrous oxide emissions in surface waters and estuaries of the Yaqui Basin as a consequence of agricultural fertilization and development; the environmental and economic impacts of the growing pig industry that currently consumes over half of the wheat produced in the Valley; remote sensing imagery to determine low and high crop field yields and human settlement patterns; water allocation policies; and linkages at the land-sea interface, in particular, the consequences of irrigated agriculture and aquaculture development for the coastal zone.

Contact
Pamela A. Matson

Funding provided by
• The Packard Foundation