Cunfer, G. and F. Krausmann. 2012. "Sustaining Agricultural Systems in the Old and New World: A Long-Term Socio-Ecological Comparison," in Long Term Socio-Ecological Research: Studies in Society-Nature Interactions Across Spatial and Temporal Scales, ed. Simron Jit Singh, Helmut Haberl, Marian Chertow, Michael Mirtl, and Martin Schmid. Berlin: Springer, 269-296.
In agricultural settings, environment shapes patterns of settlement and land use. Using the Great Plains of the United States during the period of its initial Euro-American settlement (1880–1940) as an analytic lens, this article explores whether the same environmental factors that determine settlement timing and land use–those that indicate suitability for crop-based agriculture–also shape initial family formation, resulting in fewer and smaller families in areas that are more conducive to livestock raising than to cropping. The connection between family size and agricultural land availability is now well known, but the role of the environment has not previously been explicitly tested. Descriptive analysis offers initial support for a distinctive pattern of family formation in the western Great Plains, where precipitation is too low to support intensive cropping. However, multivariate analysis using county-level data at 10-year intervals offers only partial support to the hypothesis that environmental characteristics produce these differences. Rather, this analysis has found that the region was also subject to the same long-term social and demographic changes sweeping the rest of the country during this period.
Maxwell, Susan K. and Kenneth M. Sylvester. 2012. "Identification of 'Ever-Cropped' Land (1984-2010) Using Landsat Annual Maximum NDVI Image Composites: Southwestern Kansas Case Study." Remote Sensing of Environment 121: 186-195.
A time series of 230 intra- and inter-annual Landsat Thematic Mapper images was used to identify land that was ever cropped during the years 1984 through 2010 for a five county region in southwestern Kansas. Annual maximum Normalized Difference Vegetation Index (NDVI) image composites (NDVIann-max) were used to evaluate the inter-annual dynamics of cropped and non-cropped land. Three feature images were derived from the 27-year NDVIann-max image time series and used in the classification: 1) maximum NDVI value that occurred over the entire 27 year time span (NDVImax), 2) standard deviation of the annual maximum NDVI values for all years (NDVIsd), and 3) standard deviation of the annual maximum NDVI values for years 1984–1986 (NDVIsd84–86) to improve Conservation Reserve Program land discrimination.
Results of the classification were compared to three reference data sets: County-level USDA Census records (1982–2007) and two digital land cover maps (Kansas 2005 and USGS Trends Program maps (1986–2000)). Area of ever-cropped land for the five counties was on average 11.8% higher than the area estimated from Census records. Overall agreement between the ever-cropped land map and the 2005 Kansas map was 91.9% and 97.2% for the Trends maps. Converting the intra-annual Landsat data set to a single annual maximum NDVI image composite considerably reduced the data set size, eliminated clouds and cloud-shadow affects, yet maintained information important for discriminating cropped land. Our results suggest that Landsat annual maximum NDVI image composites will be useful for characterizing land use and land cover change for many applications. Cunfer, G. 2011. "The Southern Great Plains Wind Erosion Maps of 1936-1937." Agricultural History 85: 540-559.
In 1936-1937 the US Soil Conservation Service conducted a reconnaissance survey of the Dust Bowl, the area of worst wind erosion on the southern Great Plains. Providing farm-level detail and covering twenty-six counties in five states–some twenty-seven million acres or forty-two thousand square miles–this survey represents our best record of land use and soil erosion at the peak of the 1930s crisis. The project generated well-designed and information- rich maps for each county, but their graphic nature and large size has left them virtually unknown to agricultural and environmental historians of the Dust Bowl. The Historical Geographic Information Systems Laboratory at the University of Saskatchewan has now digitized these maps and built an HGIS that will allow analysis of this information for the first time in seventy-five years.
Dunlop, Andrew. Forthcoming 2011. "Local Agricultural Landscape Evolution on the Transnational Northern Great Plains, 1935-2006." In Farming Across Borders: Selections on Transnational Agricultural History in the North American West, ed. Sterling Evans. College Station: Texas A&M University Press, Chapter 5.
Hartman, M.D., E.R. Merchant, W.J. Parton, M.P. Gutmann, S.M. Lutz, and S.A. Williams. 2011. "Impact of Historical Land Use Changes in the U.S. Great Plains, 1883 to 2003." Ecological Applications. 21(4): 1105-1119.
European settlement of North America has involved monumental environmental change. From the late 19th century to the present, agricultural practices in the Great Plains of the United States have dramatically reduced soil organic carbon levels and increased greenhouse gas (GHG) fluxes in this region. This paper details the development of an innovative method to assess these processes. Detailed land use datasets that specify complete agricultural histories for 21 representative Great Plains counties reflect historical changes in agricultural practices, and drive the biogeochemical model, DAYCENT, to simulate 120 years of cropping and related ecosystem consequences. Model outputs include yields of all major crops, soil and system carbon levels, soil trace gas fluxes (N2O emissions and CH4 consumption), and soil nitrogen mineralization rates. Comparisons between simulated and observed yields allowed us to adjust and refine model inputs, and then to verify and validate the results. These verification and validation exercises produced measures of model fit that indicated the appropriateness of this approach for estimating historical changes in crop yield. Plowout of native grass and continued farming produced a significant loss of soil C over decades, and declining soil fertility led to reduced crop yields. This process was accompanied by a large GHG release, which subsided as soil fertility decreased. Later, irrigation, nitrogen fertilizer application, and reduced cultivation intensity restored soil fertility and increased crop yields, but led to increased N2O emissions that reversed the decline in net GHG release. By drawing on both historical evidence of land use change and scientific models that estimate the environmental consequences of those changes, this article offers an improved way to understand the short- and long-term ecosystem effects of 120 years of cropping in the Great Plains.
Recent debate in the literature on population, environment, and land use questions the applicability of theory that patterns of farm extensification and intensification correspond to the life course of farmers and to the life cycle of farm families. This paper extends the debate to the agricultural development of the United States Great Plains region, using unique data from 1875 to 1930 that link families to farms over time in 25 environmentally diverse Kansas townships. Results of multilevel statistical modeling indicate that farmer's age, household size, and household structure are simultaneously related to both the extent of farm operations and the intensity of land use, taking into account local environmental conditions and time trends as Kansas was settled and developed. These findings validate farm- and life cycle theories and offer support for intergenerational motivations for farm development that include both daughters and sons. Environmental variation in aridity was a key driver of farm structure.
Gutmann, M.P., G.D. Deane, and K. Witkowski. 2011. "Finding Frontiers in the U.S. Great Plains from the End of the Civil War to the Eve of the Great Depression." In Navigating Time and Space in Population Studies, ed. M.P. Gutmann, G.D. Deane, E.R. Merchant, and K.M. Sylvester. New York: Springer, 161-183.
This chapter uses a new approach to studying patterns of spatial settlement to understand the forces that shaped the movement of the European-origin population into the semi-arid and arid natural region referred to as the Great Plains of the United States, between 1880 and 1940. Defining settlement as the process by which each of the roughly 500 counties in the region reached a population density threshold of four persons per square mile, the results evaluate hypotheses that suggest that the most important forces at work were a combination of structural attributes of the national process (population moving from east to west), climate (precipitation, temperature), other resources inside the region (irrigation, transportation, energy, employment in industry), and developments outside the region, such as the need to supply food to gold and silver miners working in the mountainous region to the west. The approach taken in the chapter includes a new strategy for working with changing county boundaries, and a statistical method employing Cox proportional hazards models for repeated events. The results reveal a process of settlement diffusion in the Great Plains, and demonstrate that variations in that diffusion process favored areas well-suited to cropping, mining, and manufacturing.
The massive publicity surrounding the exodus of residents from New Orleans spurred by Hurricane Katrina has encouraged interest in the ways that past migration in the U.S. has been shaped by environmental factors. So has Timothy Egan's exciting book, The Worst Hard Time: The Untold Story of those who survived the Great American Dust Bowl. This article places those dramatic stories into a much less exciting context, demonstrating that the kinds of environmental factors exemplified by Katrina and the Dust Bowl are dwarfed in importance and frequency by the other ways that environment has both impeded and assisted the forces of migration. We accomplish this goal by enumerating four types of environmental influence on migration in the U.S.: (1) environmental calamities, including floods, hurricanes, earthquakes, and tornadoes, (2) environmental hardships and their obverse, short-term environmental benefits, including both drought and short periods of favorable weather, (3) environmental amenities, including warmth, sun, and proximity to water or mountains, and (4) environmental barriers and their management, including heat, air conditioning, flood control, drainage, and irrigation. In U.S. history, all four of these have driven migration flows in one direction or another. Placing Katrina into this historical context is an important task, both because the environmental calamities of which Katrina is an example are relatively rare and have not had a wide impact, and because focusing on them defers interest from the other kinds of environmental impacts, whose effect on migration may have been stronger and more persistent, though less dramatic.
Cunfer, G and Krausmann, F. 2009. "Sustaining Soil Fertility: Agricultural Practice in the Old and New Worlds." Global Environment 4: 8-47.
Farms stood at an ecological frontier in the 1930s. With new and better agricultural machinery, more farms than ever before made the leap to thousand acre enterprises. But did they abandon mixed husbandry in the process? This article explores the origins of the modern relationship between scale and diversity using a new sample of Kansas farms. In 25 townships across the state, between 1875 and 1940, the evidence demonstrates that relatively few plains farms were agents of early monoculture. Rather than a process driven by single-crop farming, settlement was shaped by farms that grew more diverse with each generation.
The Green Revolution of the 1960s brought about a dramatic rise in global crop yields. But, as most observers acknowledge, this has come at a considerable cost to biodiversity. Plant breeding, synthetic fertilizers, and mechanization steadily narrowed the number of crop varieties commercially available to farmers and promoted fencerow-to-fencerow monocultures. Many historians trace the origins of this style of industrialized agriculture to the last great plow-up of the Great Plains in the 1920s. In the literature, farms in the plains are often described metaphorically as wheat factories, degrading successive landscapes. While in many ways these farms were a departure from earlier forms of husbandry in the American experience, monocultures were quite rare during the early transformation of the plains. Analysis of a large representative sample, based on manuscript agricultural censuses and involving twenty-five townships across the state of Kansas, demonstrates that diverse production reached even the most challenging of plains landscapes.
Cunfer, G. 2008. "Scaling the Dust Bowl." In Placing History: How Maps, Spatial Data, and GIS Are Changing Historical Scholarship, ed. A.K. Knowles. Redlands: ESRI Press, 95-121.
Cunfer, G. 2008. "Creating the Dust Bowl: Making History, Making Art." A digital supplement to Placing History: How Maps, Spatial Data, and GIS Are Changing Historical Scholarship, ed. A.K. Knowles Redlands: ESRI Press.
Parker, D.C., B. Entwisle, R.R. Rindfuss, L.K. Vanwey, S.M. Manson, E.F. Moran, Li An, P. Deadman, T.P. Evans, M. Linderman, S.M. Mussavi Rizi, and G. Malanson. 2008. "Case Studies, Cross-Site Comparisons, and the Challenge of Generalization: Comparing Agent-Based Models of Land-Use Change in Frontier Regions." Journal of Land Use Science. 3: 41-72.
Cross-site comparisons of case studies have been identified as an important priority by the land-use science community. From an empirical perspective, such comparisons potentially allow generalizations that may contribute to production of global-scale land-use and land-cover change projections. From a theoretical perspective, such comparisons can inform development of a theory of land-use science by identifying potential hypotheses and supporting or refuting evidence. This paper undertakes a structured comparison of four case studies of land-use change in frontier regions that follow an agent-based modeling approach. Our hypothesis is that each case study represents a particular manifestation of a common process. Given differences in initial conditions among sites and the time at which the process is observed, actual mechanisms and outcomes are anticipated to differ substantially between sites. Our goal is to reveal both commonalities and differences among research sites, model implementations, and ultimately, conclusions derived from the modeling process.
Rindfuss, R. R., B. Entwisle, S.J. Walsh, Li An, N. Badenoch, D.G. Brown, P. Deadman, T.P. Evans, J. Fox, J. Geoghegan, M.P. Gutmann, M. Kelly, M. Linderman, J. Liu, G.P. Malanson, C.F. Mena, J.P. Messina, E.F. Moran, D. Parker, W.J. Parton, P. Prasartkul, D. Robinson, Y. Sawangdee, L.K. Vanwey, P. Verburg, G. Zhong. 2008. "Land Use Change: Complexity and Comparisons." Journal of Land Use Science. 3: 1-10.
The objective of this paper is to examine issues in the inclusion of simulations of ecosystem functions in agent-based models of land use decision-making. The reasons for incorporating these simulations include local interests in land fertility and global interests in carbon sequestration. Biogeochemical models are needed in order to calculate such fluxes. The Century model is described with particular attention to the land use choices that it can encompass. When Century is applied to a land use problem the combinatorial choices lead to a potentially unmanageable number of simulation runs. Century is also parameter-intensive. Three ways of including Century output in agent-based models, ranging from separately calculated look-up tables to agents running Century within the simulation, are presented. The latter may be most efficient, but it moves the computing costs to where they are most problematic. Concern for computing costs should not be a roadblock.
Sylvester, Kenneth M. and Myron P. Gutmann. 2008. "Changing Agrarian Landscapes Across America: A Comparative Perspective." In Agrarian Landscapes in Transition, ed. Charles Redman and David Foster. New York: Oxford University Press.
Sylvester, Kenneth M. and Gutmann, Myron P. 2008. "Dustbowl Legacies: Long Term Change and Resilience in the Shortgrass Steppe." In Agrarian Landscapes in Transition, ed. Charles Redman and David Foster. New York: Oxford University Press.
Bioenergy cropping systems could help offset greenhouse gas emissions, but quantifying that offset is complex. Bioenergy crops offset carbon dioxide emissions by converting atmospheric CO2 to organic C in crop biomass and soil, but they also emit nitrous oxide and vary in their effects on soil oxidation of methane. Growing the crops requires energy (e.g., to operate farm machinery, produce inputs such as fertilizer) and so does converting the harvested product to usable fuels (feedstock conversion efficiency).
The objective of this study was to quantify all these factors to determine the net effect of several bioenergy cropping systems on greenhouse-gas (GHG) emissions. We used the DAYCENT biogeochemistry model to assess soil GHG fluxes and biomass yeilds for corn, soybean, alfalfa, hybrid poplar, reed canarygrass, and switchgrass as bioenergy crops in Pennsylvania, USA. DAYCENT results were combined with estimates of fossil fuels used to provide farm inputs and operate agricultural machinery and fossil-fuel offsets from biomass yields to calculate net GHG fluxes for each cropping system considered. Displaced fossil fuel was the largest GHG sink, followed by soil carbon sequestration. N2O emissions were the largest GHG source. All cropping systems considered provided net GHG sinks, even when soil C was assumed to reach a new steady state and C sequestration in soil was not counted. Hybrid poplar and switchgrass provided the largest net GHG sinks, >200 g CO2e-Cm-2yr-1 for biomass conversion to ethanol, and >400 g CO2e-Cm-2yr-1 for biomass gasification for electricity generation. Compared with the life cycle of gasoline and diesel, ethanol and biodiesel from corn rotations reduced GHG emissions by ~40%, reed canarygrass by ~85%, and switchgrass and hybrid poplar by ~115%.
Despite concern about the social, economic, and ecological viability of the agricultural Great Plains, a century-long examination reveals that threats to society, economy, and environment are counterbalanced by surprising stability and the potential for short- and medium-term sustainability.
Populations in metropolitan counties have grown, whereas rural populations may now be stable; both metropolitan and rural populations are aging. Technological advances in the past five decades enhanced production in the Great Plains despite periodic adverse economic and environmental conditions, and increases in crop yields, animal feeding, and government payments have sustained agriculture and income. Nonmetropolitan counties with irrigated farming have been more successful than those without irrigation. However, overuse of groundwater and rising energy costs for irrigation affect conomic margins and the ability to sustain environmental integrity.
Long-term projections of agricultural productivity must balance recent stability with the risks posed by reduced irrigation, higher energy prices, disruptive demographic changes, and further loss of environmental integrity.
Del Grosso, S.J., W.J. Parton, A.R. Mosier, M.K. Walsh, D.S. Ojima, and P.E. Thornton. 2006. "DAYCENT National-Scale Simulations of Nitrous Oxide Emissions from Cropped Soils in the United States." Journal of Environmental Quality. 35: 1451-1460.
Until recently, Intergovernmental Panel on Climate Change (IPCC) emission factor methodology, based on simple empirical relationships, has been used to estimate carbon (C) and nitrogen (N) fluxes for regional and national inventories. However, the 2005 USEPA greenhouse gas inventory includes estimates of N2O emissions from cultivated soils derived from simulations using DAYCENT, a process-based biogeochemical model.
DAYCENT simulated major U.S. crops at county-level resolution and IPCC emission factor methodology was used to estimate emissions for the approximately 14% of cropped land not simulated by DAYCENT. The methodology used to combine DAYCENT simulations and IPCC methodology to estimate direct and indirect N2O emissions is described in detail. Nitrous oxide emissions from simulations of presettlement native vegetation were subtracted from cropped soil N2O to isolate anthropogenic emissions. Meteorological data required to drive DAYCENT were acquired from DAYMET, an algorithm that uses weather station data and acounts for topography to predict daily temperature and precipitation at 1-km2 resolution. Soils data were acquired from the State Soil Geographic Database (STATSGO). Weather data and dominant soil texture class that lie closest to the geographical center of the largest cluster of cropped land in each county were used to drive DAYCENT. Land management information was implemented at the agricultural-economic region level, as defined by the Agricultural Sector Model. Maps of model-simulated county-level crop yields were compared with yields estimated by the USDA for quality control.
Combining results from DAYCENT simulations of major crops and IPCC methodology for remaining cropland yielded estimates of approximately 109 and approximately 70 Tg CO2 equivalents for direct and indirect, respectively, mean annual anthropogenic N2O emissions for 1990-2003.
Haberl, Helmut, Verena Winiwarter, Ernst Langthaler, Hermann Lotze-Campen, Michael Mirtl, Charles L. Redman, Anette Reenberg, Andrew Wardell, Benjamin Warr, Harald Zechmeister, Krister Andersson, Robert U. Ayres, Christopher Boone, Alicia Castillo, Geoff Cunfer, Marina Fischer-Kowalski, William R. Freudenburg, Eeva Furman, Rudiger Kaufmann, and Fridolin Krausmann. 2006. "From LTER to LTSER: Conceptualizing the Socio-Economic Dimension of Long-Term Socio-Ecological Research." Ecology and Society. 11(2): 13.
Concerns about global environmental change challenge long term ecological research (LTER) to go beyond traditional disciplinary scientific research to produce knowledge that can guide society toward more sustainable development.
Reporting the outcomes of a 2 d interdisciplinary workshop, this article proposes novel concepts to substantially expand LTER by including the human dimension. We feel that such an integration warrants the insertion of a new letter in the acronym, changing it from LTER to LTSER, "Long-Term Socioecological Research," with a focus on coupled socioecological systems.
We discuss scientific challenges such as the necessity to link biophysical processes to governance and communication, the need to consider patterns and processes across several spatial and temporal scales, and the difficulties of combining data from in-situ measurements with statistical data, cadastral surveys, and soft knowledge from the humanities. We stress the importance of including prefossil fuel system baseline data as well as maintaining the often delicate balance between monitoring and predictive or explanatory modeling. Moreover, it is challenging to organize a continuous process of cross-fertilization between rich descriptive and causal-analytic local case studies and theory/modeling-oriented generalizations. Conceptual insights are used to derive conclusions for the design of infrastructures needed for long-term socioecological research.
Johnson, Kenneth M. 2006. Demographic Trends in Rural and Small Town America. Durham: Carsey Institute.
In the next decades, aging farmers in the United States will make decisions that affect almost 1 billion acres of land. The future of this land will become more uncertain as farm transfer becomes more difficult, potentially changing the structure of agriculture through farm consolidation, changes in farm ownership and management, or taking land out of production.
The Great Plains Population and Environment Project interviewed farmers and their spouses between 1997 and 1999. Farm Family Survey participants were ambiguous about their plans to leave farming, transfer land to others, and even long-term land use, largely due to concerns about the continued economic viability of farming. Participants living far from metropolitan areas expected to sell or rent to other farmers, while those near residential real-estate markets expected to sell to developers. Delays in planning for retirement and succession were common, further threatening the success of intergenerational transitions.
Cunfer, Geoffrey. 2005. On the Great Plains: Agriculture and Environment. College Station: Texas A&M University Press.
Del Grosso, S.J., A.R. Mosier, W.J. Parton, and D.S. Ojima. 2005. "DAYCENT Model Analysis of Past and Contemporary Soil N2O and Net Greenhouse Gas Flux for Major Crops in the U.S.A." Soil Tillage and Research. 83: 9-24.
The DAYCENT ecosystem model (a daily version of CENTURY) and an emission factor (EF) methodology used by the Intergovernmental Panel on Climate Change were used to estimate direct and indirect N2O emission for major cropping systems in the USA. The EF methodology is currently used for the USA greenhouse gas inventory but process based models, such as DAYCENT, may yield more reliable results because they account for factors such as soil type, climate, and tillage intensity that are ignored by EF.
Comparison of mean annual soil N2O flux estimated by DAYCENTand EF with measured data for different cropping systems yielded r2 values of 0.74 and 0.67, and mean deviations of -6 and +13%, respectively. At the national scale, DAYCENT simulation of total N2O emission was ~25% lower than estimated using EF. For both models, N2O emission was highest in the central USA followed by the northwest, southwest, southeast, and northeast regions. The models simulated roughly equivalent direct N2O emission from fertilized crops, but EF estimated greater direct N2O emission than DAYCENT for N-fixing crops. DAYCENTand EF estimates of the gaseous component of indirect N2O emission (NO + NH3) differed little, but DAYCENTestimated approximately twice the indirect emission from NO3 leaching since it included the contribution of N from N-fixing crops while EF did not.
DAYCENT simulations were also performed for no tillage cropping, pre-1940 crop management, and native vegetation. DAYCENT-simulated N2O, CO2, and CH4 fluxes were converted to CO2-C equivalents and combined with fuel use estimates to estimate net global warming potential (GWPnet). GWPnet for recent non-rice (Oryza sativa L.) major cropping was 0.43 Mg C ha-1 yr-1 under conventional tillage and 0.29 Mg C ha-1 yr-1 under no tillage, for pre-industrial cropping was 0.25 Mg C ha-1 yr-1, and for native systems was -0.15 Mg C ha-1 yr-1. Results from DAYCENT suggest that conversion to no tillage at the national scale could mitigate ~20% of USA agricultural emission or ~1.5% of total USA emission of greenhouse gases.
Gutmann, Myron P., William J. Parton, Geoff Cunfer, and Ingrid C. Burke. 2005. "Population and Environment in the U.S. Great Plains." In New Research on Population and the Environment, ed. B. Entwisle and P. Stern, 84-105. Washington, D.C.: National Academy Press.
Gutmann, Myron P., Glenn Deane, Nathan Lauster, and Andres Peri. 2005. "Two Population-Environment Regimes in the Great Plains of the United States, 1930-1990." Population and Environment. 27(2): 191-225.
This paper analyzes factors that affect net migration rates in counties in the U.S. Great Plains between 1930 and 1990, emphasizing the roles of weather (especially drought), environmental amenities, employment, and population, making use of a rich county-level data set. Using a pooled time series model the paper shows that environment is important in population processes, with weather and agricultural change more important in the 1930s and 1940s, and environmental amenities more important in later time periods. The paper provides important insights into how environmental impacts on migration might change over time, and how those changes might be measured.
Gutmann, Myron P. 2005. Great Plains Population and Environment Data: Agricultural Data. Ann Arbor: Inter-university Consortium for Political and Social Research, 4254.
Gutmann, Myron P. 2005. Great Plains Population and Environment Data: Social and Demographic Data. Ann Arbor: Inter-university Consortium for Political and Social Research, 4296.
Johnson, Kenneth M., Paul R. Voss, Roger B. Hammer, Glenn V. Fuguitt, and Scott McNiven. 2005. "Temporal and Spatial Variation in Age-Specific Net Migration in the United States." Demography. 42(4): 791-812.
As fertility differences in the United States diminish, population redistribution trends are increasingly dependent on migration. This research used newly developed county-level age-specific net migration estimates for the 1990s, supplemented with longitudinal age-specific migration data spanning the prior 40 years, to ascertain whether there are clear longitudinal trends in age-specific net migration and to determine if there is spatial clustering in the migration patterns.
The analysis confirmed the continuation into the 1990s of distinct net migration "signature patterns" for most types of counties, although there was temporal variation in the overall volume of migration across the five decades. A spatial autocorrelation analysis revealed large, geographically contiguous regions of net in-migration (in particular, Florida and the Southwest) and geographically contiguous regions of net out-migration (the Great Plains, in particular) that persisted over time. Yet the patterns of spatial concentration and fragmentation over time in these migration data demonstrate the relevance of this "neighborhood" approach to understanding spatiotemporal change in migration.
Leonard, Susan Hautaniemi and Myron P. Gutmann. 2005. "Isolated Elderly in the U.S. Great Plains: The Roles of Environment and Demography in Creating a Vulnerable Population." Annales de Demographie Historique. 110(2): 81-108.
Parton, William J., Myron P. Gutmann, Stephen A. Williams, Mark Easter, and Dennis Ojima. 2005. "Ecological Impact of Historical Land-Use Patterns in the Great Plains: A Methodological Assessment." Ecological Applications. 15(6): 1915-1928.
This paper demonstrates a method for using historical county-level agricultural land-use data to drive an ecosystem model. Four case study counties from the U.S. Great Plains during the 19th and 20th centuries are used to represent different agroecosystems. The paper also examines the sensitivity of the estimates of county-level ecosystem properties when using different levels of detail in the land-use histories. Using weighted averages of multiple-model runs for grassland, dryland cropping, and irrigated cropping improved prediction over a simple, single-run approach that models the prevailing land use. Model runs with the same land use and environment generally reach similar levels of soil carbon and nitrogen mineralization after ~50 years, no matter when they began, with faster convergence for irrigated cropland.
Model results show that cultivation of grasslands results in large losses of soil carbon and an increase in soil nitrogen mineralization for the first 20-30 years of cultivation, which is followed by low soil carbon loss and nitrogen mineralization 50 years after cultivation started. The recently observed increase in irrigated agriculture in the central and northern Great Plains (2.7 million ha) has resulted in a net carbon storage of 21.3 Tg carbon, while irrigated cotton production has resulted in a net loss of 12.1 Tg carbon.
Baron, J.S., S. Del Grosso, D.S. Ojima, D.M. Theobald, and W.J. Parton. 2004. "Nitrogen Emissions Along the Colorado Front Range: Response to Population Growth, Land and Water Use Change, and Agriculture." In Ecosystems Interactions with Land Use Change, ed. R. DeFries and G.P. Asner, 117-129. AGU Press.
Cunfer, Geoff. 2004. "Manure Matters on the Great Plains Frontier." Journal of Interdisciplinary History. 34(4): 539-567.
Gutmann, Myron P., Sara M. Pullum, Susan Gonzalez Baker, and Ingrid C. Burke. 2004. "German-Origin Settlement and Agricultural Land Use in the Twentieth Century Great Plains." In German-American Immigration and Ethnicity in Comparative Perspective, ed. W. Kamphoefner and W. Helbich, 138-168. Madison: University of Wisconsin Press.
Deane, Glenn and Gutmann, Myron P. 2003. "Blowin' Down the Road: Investigating Bilateral Causality Between Dust Storms and Population in the Great Plains." Population Research and Policy Review. 22(4): 297-331.
Recently, the National Academy of Sciences concluded "it is clear that population and environment are usually interrelated...". This paper directly tests the expected interrelationship using annual county-level population estimates provided by the U.S. Census Bureau and annual counts of dust storms from the 1960s, '70s, and '80s at weather stations situated throughout the U.S. Great Plains. In doing so, it implements a research design that extends methods (far removed from conventional demography) for pure time series analysis with multilevel regression models. The result is a method for causal modeling in panel data that produces, in this application, evidence of bilateral causality between population size and deleterious environmental conditions.
Parton, William J., Myron P. Gutmann, and William R. Travis. 2003. "Sustainability and Historical Land-Use Change in the Great Plains: The Case of Eastern Colorado." Great Plains Research. 13: 97-125.
The Great Plains is one focus of the debate in the United States over appropriate land use and sustainability. Within the Plains region, eastern Colorado represents a case study that permits researchers and policymakers to focus on important relationships between agricultural land use, population change, and the sustainability of agriculture, environment, and communities. Colorado Front Range urban areas experienced large increases in population from 1950 to 2000 that resulted in a 35% reduction in total farmland. In the urban fringe region, farmers declined rapidly since 1978 and harvested irrigated cropland declined by 16% since 1990. Rural population in eastern Colorado decreased from 1950 to 1970 and then stabilized. Rural areas experienced decreased total farmland, harvested dryland, and rangeland, as well as intensification of agriculture because of a 76% increase in harvested irrigated land (1950 to 1997). Inflation-adjusted agricultural product income remained stable because of large increases in crop yield from irrigated crops and animal production. The surprising result of this analysis is that agriculture and population are not declining throughout the Great Plains.
Burke, Ingrid C., William K. Lauenroth, Geoff Cunfer, John E. Barrett, Arvin Mosier, and Petra Lowe. 2002. "Nitrogen in the Central Grasslands Region of the United States." Bioscience. 59(9): 813-823.
Gutmann, Myron P., Sara M. Pullum-Pinon, and Thomas W. Pullum. 2002. "Three Eras of Young Adult Home Leaving in Twentieth-Century America." Journal of Social History. 35(3): 533-576.
Sylvester, Kenneth M., Susan H. Leonard, Myron P. Gutmann, and Geoff Cunfer. 2002. "Demography and Environment in Grassland Settlement: Using Linked Longitudinal and Cross-Sectional Data to Explore Household and Agricultural Systems." History and Computing. 14(1-2): 31-60.
Cunfer, Geoff. 2001. "The New Deal's Land Utilization Program in the Great Plains." Great Plains Quarterly. 21: 193-210.
In order to quantify the historical changes in carbon storage that result from agricultural conversion, this study compared the carbon dynamics of two sites in the loess region of Iowa: a native prairie and a cropland. Field data were obtained to determine present-day carbon storage and its variability within a landscape (a stable ridgetop vs. eroding upper-midslope vs. depositional lower slope). Models were used to recreate the historical carbon budget of these sites and determine the cropland's potential to be a net CO2 source or sink, relative to the atmosphere.
Regardless of slope position, the cropland site contains approximately half the amount of carbon as prairie. Variability in soil carbon storage within a site as a consequence of slope position is as large or larger (variations of 200+/-300%) than temporal variation (~200% at all slope positions). The most extreme difference in soil carbon storage between the cropland and prairie sites is found in the soil at the upper-midslope, which is the area of greatest erosion. The models estimate that 93+/-172% of the carbon in the original topsoil has been lost from the cropland's eroding midslope. Much of this carbon is derived from deeper soil horizons. Either a small sink or strong source of carbon to the atmosphere is created, depending on the fate of the eroded sediment and its associated carbon.
This paper is about the scales at which demographic data are available, and demographic research is conducted, and their implications for understanding the relationship between population and environment. It describes a multi-disciplinary project designed to study the long-term relationship between population, land use, and environment in the U.S. Great Plains.
The paper begins with a discussion of the scales at which data are readily available for demographic, agricultural land use, and environmental data for the United States. Some of these data can be obtained at relatively high resolutions, but the lowest common denominator for many of the long term data is the county, a fairly large unit. I then discuss the advantages and disadvantages of the different scales available. The third section of the paper uses county net migration as an example of research that can be done, and the scale at which it is effective. The example shows that the county is an effective unit for the study of migration, and that the research results are significant. The conclusion suggests that the study of population processes in an environmental and economic context is appropriate at the county level for some questions, but that scaling the results to larger units may be difficult because of the need to be certain about the contexts in which those processes take place. We probably should not study net migration at the national or continental scale, but aggregating county-level or regional studies to a larger scale may be successful.
Farmers insert themselves into natural systems and manipulate those systems to accomplish human goals; in turn, natural systems constrain farmers and limit their ability to reach their goals. That interaction shifts through time as physical systems evolve and human land use decisions change. To understand how people interact with nature the place to start is agriculture, where the interface is crucial on a daily basis and the affected landscape is global in extent. This dissertation evaluates a century of interaction between farmers and nature in the Great Plains. It assesses human manipulation of natural processes as farming evolved between American settlement in the 1870s and the modern farm system in place by the 1970s. The ecological state of the Great Plains at any point in its history has been a joint creation of human and natural forces.
Case studies of communities in the Great Plains form the foundation of the work. Rooks County, Kansas had a history of homesteading followed by a century of dryland farming. Golden Valley County, North Dakota represents two dozen locations where New Deal agencies in the 1930s converted private land back to public domain to be bureaucratically managed. Crosby County, Texas weathered the Dust Bowl before converting to widespread irrigation from the Ogallala Aquifer. Although they have much in common, each location followed a different historical trajectory as farmers both responded to and molded natural systems.
One chapter assesses ecological changes revolving around the move from horses to tractors on farms. Each system had distinct ecological requirements and consequences. Another chapter addresses changes in plant diversity while a third evaluates shifting agricultural manipulation of soil nutrient cycles. Two chapters describe changing cultural use of common lands and resources, offering the move from open range to federally managed grazing reserves in North Dakota as an example. A final chapter assesses the role of groundwater irrigation in west Texas after the 1930s. It describes how exploitation of a formerly unavailable common resource affected floral diversity, nutrient cycles, and energy dynamics on the southern plains.
The Dust Bowl of the 1930s is one of the best known and most often studied of the environmental "surprises" in United States history. It was well described by its contemporaries, and powerfully presented in the visual and literary arts. Many historians have tried to explain its causes, and most of the available explanations rest on the way that farmers used the land in the 1930s. Are those explanations still appropriate? The problem with answering that question is that despite a large quantity of newly amassed data, a great deal remains to be known about land use and environment in the 1930s.
This paper presents an innovative starting point by looking at a statistical model for predicting dust activity based on data from the 1960s, 1970s, and 1980s. The paper tells us what has caused dust to blow in recent years, based on the best approach available now. Then the paper discusses whether the findings from recent decades can be extrapolated to data over a longer period of time and covering a larger area. The conclusions present the story of dust in the recent past, and some partial confirmation of the story of the 1930s. It gives renewed emphasis to the role of natural forces in the creation of the Dust Bowl.
Gutmann, Myron P. and Sara M Pullum. 1999. "From Local to National Political Cultures: Social Capital and Civic Organization in the Great Plains." Journal of Interdisciplinary History. 29(4): 725-762.
Harden, J.W., J.M. Sharpe, W.J. Parton, D.S. Ojima, T.L. Fries, T.G. Huntington, and S.M. Dabney. 1999. "Dynamic Replacement and Loss of Soil Carbon on Eroding Cropland." Global Biogeochemical Cycles. 13(4): 885-901.
Links between erosion/sedimentation history and soil carbon cycling were examined in a highly erosive setting in Mississippi loess soils. We sampled soils on (relatively) undisturbed and cropped hillslopes and measured C, N, C-14, and CO2 flux to characterize carbon storage and dynamics and to parameterize Century and spreadsheet C-14 models for different erosion and tillage histories.
For this site, where 100 years of intensive cotton cropping were followed by fertilization and contour plowing, there was an initial and dramatic decline in soil carbon content from 1870 to 1950, followed by a dramatic increase in soil carbon. Soil erosion amplifies C loss and recovery: About 100% of the original, prehistoric soil carbon was likely lost over 127 years of intensive land use, but about 30% of that carbon was replaced after 1950. The eroded cropland was therefore a local sink for CO2 since the 1950s. However, a net CO2 sink requires a full accounting of eroded carbon, which in turn requires that decomposition rates in lower slopes or wetlands be reduced to about 20% of the upland value. As a result, erosion may induce unaccounted sinks or sources of CO2, depending on the fate of eroded carbon and its protection from decomposition.
For erosion rates typical of the United States, the sink terms may be large enough (1 Gt yr(-1), back-of-the-envelope) to warrant a careful accounting of site management, cropping, and fertilization histories, as well as burial rates, for a more meaningful global assessment.
The central grassland region occupies the center of North America in the United States, Canada and Mexico and is a unique resource for the continent. While there are no other areas with comparable features, the largest similar grassland areas occur in Europe and Asia. The uniqueness of the region derives from its size, its relative flatness, and the smoothness of its physical gradients. The smooth gradients in precipitation and temperature are the reasons why most gradients in ecosystem properties are also smooth. The west-east gradient in precipitation and the north-south gradient in temperature result in corresponding gradients in plant community types, net biomass production by plants, soil carbon storage, and nitrogen availability to plants. One of the most striking features of the present condition of the central grassland region is that a huge fraction of the original native grassland have been replaced by cropland.
Gutmann, Myron P., Sara M. Pullum, Geoffrey A. Cunfer, Delia Hagen. 1998. Great Plains Population and Environment Database: Sources and User's Guide. Austin: Texas Population Research Center.
Lackett, J. 1998. New Measures of Conservation in Weld County, Colorado Agriculture. M.A. Thesis, Colorado State University.
Balkan, J.L. 1997. Does Population Size Matter to Agricultural Land Use? A Focus on the Great Plains. M.A. Thesis, Department of Sociology, University of Texas.