KBS is 1600 ha of cropping systems, successional communities, and small lakes. 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 Station soils are Typic Hapludalfs. Land use around KBS ranges from urban (Kalamazoo, with a metropolitan population of 160,000 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 of different morphometries, alkalinities, and degrees of eutrophication within 50 km. 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 yields elsewhere in the North Central Region. Most KBS LTER research is carried out in a series of 11 types of plant communities, ranging from annual corn-soybean-wheat rotations to late-successional deciduous forest. All communities are replicated within the landscape. Our experimental design provides four annual cropping systems managed with a range of chemical-input intensities (from full to zero chemical inputs); two perennial cropping systems (one herbaceous [alfalfa] 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 later successional oldfields abandoned from cropping 40-60 years ago, three planted conifer stands, and three older-growth 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). This allows us to test specific hypotheses from which we can better infer the ecological mechanisms that confer productivity in row-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.