Initiated in 1987, the Kellogg Biological Station LTER (KBS) examines basic ecological relationships in field crop ecosystems to better understand internal processes controlling productivity independently of external subsidies (e.g., fertilizers, pesticides). The initial goal remains the same: effectively substituting ecological knowledge and theory in the agronomic management of cropping systems for a reliance on chemically based approaches. Research involves synergistic activities of long-term observations of contrasting cropping systems and successional vegetation, shorter-term field experiments, and modeling. Hypothesis testing relates to patterns and processes underlying ecosystem productivity and nutrient retention, including plant community dynamics, soil microbial populations, insect consumer dynamics, watershed and field-scale biogeochemistry, human interactions, and regional processes. KBS-4 is organized around the same initial hypothesis, albeit with a new conceptual research model and the addition of a new focus on valuation of ecosystem services. The model organizes ecological understanding of field crop ecosystems into components focused on ecological structure (e.g., organisms and their adaptations, population and community assemblages, and habitat structure) vis a vis ecological functions (e.g., biogeochemical processes, energy capture and flow, and hydrodynamics). Linkages between these components largely define the mechanisms that underlie the production of ecosystem goods and services, those products that provide the economic and social rationale for farming. Major research topics include plant community change, microbial processes, controls of arthropod communities, biogeochemical fluxes of solutes and trace gases, human valuation of cropland ecosystem services, and regionalization (scaling up via models).

Broader Impacts. KBS is an established leader in developing and using ecological approaches to improving our understanding of agroecosystems. KBS research deals with food production, a topic of global significance, and has ready practical applications to the ongoing development of mid-western US agriculture, as well as the potential to make significant contributions to the more general area of sustainable agriculture. Outreach and educational activities are robust at KBS. Research findings are reaching the media, local and regional agricultural communities, and other key citizen groups influencing land management. KBS places a high priority on connections with agricultural policymaking and global-change issues. Several KBS scientists have testified to Congress on agricultural issues and strong international connections have been forged. The site has a significant on-the-ground outreach program offering a wide range of service and educational opportunities to the broader community including agricultural extension services, informal education, university coursework, research experience for undergraduate and graduate students, and Schoolyard LTER activities for K-12 students and educators. Contributions to the LTER network include the publication of a soils methods synthesis book and participation in the diversity x NPP and LINX network-wide studies. The site is close to full adoption of the Ecological Meta-Language (EML2) format standard to ensure easy data exchange.