The Kellogg Biological Station (KBS) is located in southwest Michigan in the eastern portion of the U.S. cornbelt, 50 km east of Lake Michigan in the SW corner of the state (42° 24′ N, 85° 24′ W, elevation 288 m). Annual rainfall at KBS averages 1,005 mm/y with about half falling as snow; potential evapotranspiration (PET) exceeds precipitation for about 4 months of the year. Mean annual temperature is 10.1 °C (NCDC climate normals, 1980-2010). KBS encompasses 1600 ha of cropping systems, successional communities, and small lakes and wetlands. Surrounding KBS is a diverse, rural-to-semirural landscape typical of the U.S. Great Lakes and upper Midwest regions. The diversity of land use, soil and vegetation types, and aquatic habitats within a 50-km radius of the Station is high. Most of southwest Michigan is on the pitted outwash plain of the morainic system left by the last retreat of the Wisconsin glaciation, circa 12,000 years ago. Soils in the area developed on glacial till, and include well- and poorly- drained alfisols, mollisols, and entisols. Most regional soils are sandy loam and silty clay loam of moderate fertility, principal KBS soils are Typic Hapludalfs.
Land use around KBS ranges from urban (Kalamazoo, with a metropolitan population of 340,000, is 20 km south of the Station) to rural; vegetation ranges from cultivated and early successional old fields to older growth oak-hickory and beech-maple forests; and aquatic habitats include more than 200 bodies of water within 50 km with different morphometries, alkalinities, and degrees of eutrophication.
Cropping systems in the area are typical of the U.S. cornbelt — mainly corn/soybean rotations with wheat of varying importance, and alfalfa an important forage crop. KBS yields are typical of non-irrigated yields nationally and elsewhere in the North Central Region. KBS LTER research is carried out in a variety of experimental systems. The most important of these is the Main Cropping System Experiment (MCSE), which was started in 1989 and consists of 11 different cropping systems or successional plant communities, ranging from annual corn-soybean-wheat rotations to late-successional deciduous forest. All communities are replicated within the KBS landscape.
The MCSE experimental design provides four annual cropping systems managed with a range of chemical-input intensities (from full to zero synthetic chemical inputs); two perennial cropping systems (one herbaceous [changed from alfalfa to switchgrass in 2019] and the other woody [Populus sp.]); and two successional communities (one historically tilled and one never tilled). In 1993 we added three additional communities to the design, for a total of 5 unmanaged communities that now include three mid-successional fields (now aggrading forests) abandoned from cropping 60-70 years ago, three planted conifer stands, and three late successional hardwood stands. The design thus provides a wide range of replicated communities with the same pedogenic history that differ in key ecological characteristics (e.g. plant species diversity, productivity, litter quality, microclimate). It allows us to test specific hypotheses from which we can better infer the ecological mechanisms that confer productivity in field-crop ecosystems – mechanisms that can then be tested with specific manipulative experiments. Baseline measurements are taken from all 11 community types, but not all communities are used to test every project hypothesis.
In 2006 we added 27 commercially managed fields at KBS to test the scalability of our research plots. These scale-up fields were managed as corn-soybean-wheat rotations after one of our three cropping system treatments (conventional, low-input, and organic). Every phase of the rotation was represented each year. This experiment was retired in 2013 (see Kravchenko et al. 2017).
A number of other long-term experiments are maintained as part of the LTER research base. These include a biodiversity gradient, a nitrogen × water resource gradient, an N-deposition experiment, and a cellulosic biofuels diversity experiment. A major set of agronomic field trials called the Living Field Lab experiment was retired in 2013. In 2008 we established additional biofuel experiments in association with DOE’s Great Lakes Bioenergy Research Center (GLBRC); these include the Biofuel Cropping System Experiment (BCSE) – a major intensive field experiment close to the MCSE, a nitrogen gradient experiment with switchgrass, a scale-up experiment at KBS’ Lux Arbor and Marshall Farm, and several smaller experiments.
For a more complete site description please see Robertson and Hamilton (2015).
Robertson, G. P. and S. K. Hamilton. 2015. Long-term ecological research in agricultural landscapes at the Kellogg Biological Station LTER site: Conceptual and experimental framework. Pages 1-32 in S. K. Hamilton, J. E. Doll, and G. P. Robertson, editors. The Ecology of Agricultural Landscapes: Long-Term Research on the Path to Sustainability. Oxford University Press, New York, New York, USA.