The North Central Region, one of several regions designated for administrative purposes by the U.S. Department of Agriculture (USDA), encompasses 12 midwestern states containing portions of the "Corn Belt." These are Ohio, Indiana, Illinois, Missouri, Michigan, Wisconsin, Minnesota, Iowa, North Dakota, South Dakota, Nebraska, and Kansas. The Corn Belt is one of the most productive agricultural regions in the world, and it includes six states bordering the Great Lakes (Ohio, Iowa, Michigan, Illinois, Wisconsin, Minnesota) and four states containing portions of the Great Plains (North Dakota, South Dakota, Nebraska, Kansas). Iowa is located in the central Corn Belt, and Missouri, with its agriculturally rich "boot heel," is the region's southern limit. Several great rivers, including the Ohio, the Mississippi, the Red River of the North, the Missouri, and the Platt, all flow within the region. The NCR spans several ecological and climatic zones. Row-crop agriculture, consisting of corn and soybean, dominates the region's agriculture.

The Corn Belt has been cropped intensively since the discovery of its rich soil base and a climate conducive for the production of row crops. These include government-supported crops such as corn, soybeans, and wheat. The intense cultivation of these crops (continuous planting of crops like corn) has required increased use of fertilizers, herbicides, insecticides, and irrigation to sustain high production levels. As a result, many of the region's fragile landscapes are facing critical issues, including reduction of soil fertility through monoculture cropping, loss of topsoil as the result of erosion, increased contamination of groundwater through leaching of chemical inputs, and depletion of subsurface water supplies through irrigation practices. Increasing pressures will be placed on the landscape not only to produce human food and livestock feed for U.S. consumption and foreign export, but also to generate biofuels to satisfy increasing energy demands in the United States (Gever et al. 1986).

The Kellogg Biological Station is one of the Long Term Ecological Research sites (KBS LTER) supported by the National Science Foundation (NSF) and is located in southwest Michigan within the eastern portion of the Corn Belt. One objective of the NSF LTER program is to enable research findings from an LTER site to represent larger ecosystems or management regimes as an aid to regional-scale decision making. "The environmental issues confronted in the second half of the 20th century approached the problem from the perspective of stressor, impact and mitigation. The environmental issues of the coming century will be resolved at the system level. En vironmental problems within landscapes and ecosystems will, of necessity, be approached from a regional perspective. It is from a regional perspective that the LTER sites will become a distributed center for the strategic research required to meet these challenges . . ." (Bruce Hayden, pers. comm., 1998). Regional-scale issues include net primary productivity dynamics, land use and cover change, dynamics of crop productivity, and climate change and related plant and insect distribution change. The NSF LTER network has attempted to assist LTER scientists address the regional representation of LTER sites through three workshops that focused on regional analysis and synthesis (Helly et al. 1998; Fountain et al. 1999; Gage et al. 2000b).

The KBS LTER site, with its focus on row crop ecosystems, is representative of crops grown in the Midwest (corn, soybean, and wheat). Because the 12 NCR states produce about 80% of the U.S. corn and soybeans (NASS 2001), an analysis of climate impacts on crop production in the region may provide valuable information on the role of the changing climate on row-crop productivity and future trends of row-crop agriculture in the NCR.

The research objective at the KBS LTER site is to understand the ecological characteristics and drivers of row-crop agriculture with a goal of developing methods to replace chemical subsidies with appropriate ecological management systems. The focus on row-crop agriculture (corn, soybean, and wheat), and the emphasis of the effects of climate on crop production and on the ecological interrelationships associated with crop management, provide an opportunity to investigate the long-term climate dynamics in the NCR and how climate impacts crop productivity at regional scales. However, because research was initiated at KBS in 1989, the year after the 1988 drought, observations on crop production at the site were not available to incorporate into the analysis of this particular drought. Studies of the contribution of row-crop agriculture to greenhouse gas dynamics by Robertson et al. (2000) and of modeling regional crop productivity (Gage et al. 2000a, 2001) provide insight into the dynamics of regional agriculture.

There is an increasing need for an ecological perspective on current and future methods of farming and utilization of agricultural lands for agricultural production. These needs are exemplified by changing dynamics and trends in weather and climate, increasing urbanization of prime farmland, the need to predict future scenarios associated with management of sensitive ecosystems, appropriate management of bioengineered crops, and development of new crop varieties.

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