A new study suggests that agriculture can successfully coexist with continuing population growth and urban sprawl in some areas of the Great Plains.
The study, conducted by researchers at the University of Michigan, Colorado State University and the University of Colorado, found that despite explosive population growth over the last 50 years in Denver, Boulder and other eastern Colorado Plains cities, total harvested area in the region increased by 5 percent and the amount of irrigated land that is harvested jumped by 73 percent.
"These findings underscore the importance of irrigation in sustaining Great Plains agriculture," said U-M historian Myron P. Gutmann, who directs The Great Plains Population and Environment Project, a multi-disciplinary, federally funded study of the long-term relationships between human population and environment in 12 Great Plains states.
Gutmann co-authored the study, to be published this spring in the journal Great Plains Research, with Colorado State University researcher William J. Parton and William R. Travis from the University of Colorado at Boulder.
"I think we were all surprised to find irrigated agriculture expanding in an area where water is also being transferred to the cities," said Travis, a professor of geography. "Of course, when a farm is bought and subdivided or paved over, that is a loss of agriculture. But we show that agriculture can thrive near an expanding urban area more than people have imagined.
"The great question for the future is whether an agriculture more and more reliant on irrigation can co-exist with thirsty cities," he said. "I think it can, but the other authors are more pessimistic and the article conveys their sense of an eventual clash."
The study analyzed employment and agricultural census data for 27 Colorado Plains counties to explore changes in land use and agricultural productivity and employment over the last half century, reaching some surprising conclusions about how those changes are linked to population size, the growth of cities and the use of irrigation.
After large declines in agricultural employment from 1950 to 1970, the study found, farm and ranch employment in the region has generally remained stable, with the smallest declines occurring in urban fringe regions. This finding suggests that urbanization might not be as bad for farming as many people think, said Parton and Gutmann, who also directs the Inter-University Consortium for Political and Social Research, the world's largest computerized social science archive and an affiliate of the U-M Institute for Social Research.
"The persistence of agriculture despite larger urban populations, smaller rural populations and declining farmland and total cropland is surprising," said Parton, the lead author of the study and senior research scientist at CSU's Natural Resource Ecology Laboratory. "The key to this persistence has been the growth of irrigation plus the economically sustaining role played by nearby urban areas and their associated transportation links."
Rather than threatening agriculture, urban development and sprawl in the region seem to have stabilized farm and ranch production by increasing demand for hay and stimulating job growth in the agricultural service sector, Parton and Gutmann note.
"In the face of drought and growing water demands in both urban and agricultural areas, the role of irrigation in sustaining Great Plains agriculture will become more uncertain," the authors wrote.
The research was funded by the National Institute of Child Health and Human Development.