This project will initiate a long-term integrated study of interactions among organisms in agricultural ecosystems. The general goal is to test the hypothesis that management based on ecological concepts can effectively substitute for reliance on chemical subsidies in production-level agronomy. By imposing a range of management treatments on a series of experimental plots specific hypotheses will be tested that follow from the general hypothesis that nutrient subsidies can be minimized by manipulating plant-microbe interactions; that herbicide subsidies can be minimized by manipulating crop-weed interactions; and that pesticide subsidies can be minimized by manipulating plant- insect-pathogen-vertebrate interactions. Primary experimental treatments are designed to alter radically the controls on population-level interactions in agronomic systems. This will allow the testing of hypotheses about how long-term interactions among populations affect system- wide attributes such as nutrient availability, herbivory and pathogenesis, plant competition, and systemswide carbon allocation and nutrient/pesticide outputs. Treatments will include four main species-levels with two management levels nested within each: conventional corn/soybean cultivation (moldboard plowed vs. no-till), organic-based, low-input corn/soybean/cover cultivation (minimum chemical input vs.zero chemical input); short-rotation Populus (woody biomass) cultivation (above ground allocation vs. belowground allocation); and native successional vegetation (historically-tilled vs. never-tilled). These treatments will be established within the same general area, and the development of these systems will be followed indefinitely. Selected satellite sites in other portions of the landscape will also be examined to formulate a basis for addressing landscape-level questions in later phases of the project. Many would assert that the future of modern agriculture demands a basic, mechanism-level understanding of the ecology of production-level cropping systems. This endeavor requires a multidisciplinary, long-term approach at a site that is relevant to North American agronomy and that can provide the logistical support and administrative infrastructure to facilitate this type of major research effort. The project team for this research is excellent comprising a broad and appropriate array of expertise and very productive records of past performance. Institutional facilities are excellent at both the main campus and at the Kellogg Biological Station (KBS) field site. Institutional commitment to the project is substantial, both as direct support and in kind. It is expected that this project will rapidly establish itself as an invaluable collaborator within the extant family of related projects and that it will provide an instructive suite of comparisons for work on unmanaged, natural ecosystems. A large number of other related research projects will continue to be conducted at the KBS and will both benefit from and lend strength to this new work. It is recommended that this new, five-year continuing award be made as requested.
