The key to the agricultural ecosystem; Ecology and agriculture; Research in agricultural ecosystems; Opportunities for research on nutrient cycling in agricultural ecosystems in Scotland; Opportunities for research in agricultural ecosystems; Opportunities for research on nitrient cycling in agricultural ecosystems in Scotland; Opportunities for research in agricultural ecosystems: Sweden; Traditional and innovative approaches to agriculture on Amazon Brasil Tierra Firme Sites; Agroecosystems of the Great Plains of North America; Research in agricultural ecosystems: North Central United States; Nutrient cycling research needs in Northeastern agriculture; Soil and water resources available for agricultural development in the Southeastern United States; Nutrient balances in agricultural ecosystems; Use of microcosms for monitoring nutrient-cycling processes in agroecosystems; Factors influencing nitrogen fluxes in a small Ontario agricultural watershed; N and P in soils and runoff of three coastal plain land uses; Nitrogen inputs and outputs for an irrigated corn ecosystem in the northwest corn belt; Movement of nutrients and sediment from a subsurface drainage system; Element mass balances for South Carolina coastal plain watersheds; Hydrology and nutrient and sediment movement from southeastern coastal plain watersheds; Nutrient cycling in a southeastern United States Agricultural Watershed; Agricultural management techniques and nutrient-cucling processes; N-15 abundances in Virgin Soils and their fertilized analogues; Nitrogen fertilization, mineralization, and leaching under irrigation in the midwest; The influence of roots on nutrient leaching and uptake; Gaseous ammonia transport in a cattle-pasture system; Fate of nitrogen from NH4N03 and broiler litter applied to coastal bermudagrass; Effects of litter-free poultry manure on nitrogen mineralization and yields of sudangrass and sorghum x sudangrass cultivars; Nitrogen and phosphorus cycling in shallow reservoirs used for agricultural drainage water treatment; Crop residue removai: the effects on soil erosion and nutrient loss; The effects of tillage on the nitrogen cycle in corn and wheat production; Nutrient and sediment losses associated with conventional and reduced-tillage agricultural practices; Effect of tillage on nutrient cycling in southeastern coastal plain agroecosystems; Riparian vegetation as filters of nutrients exported from a coastal plain agricultural watershed; Models of nutrient cycling in agricultural ecosystems; Biogeochemical cycles and ecological hierarchies; Identification and characterization of ecosystems at different integrative levels; Simulation of soil organic matter formations and mineralization in semiarid agroecosystems; Modeling nutrient cycling in agroecosystems; Simulation models of nitrogen flux in conventional and no-tillage agroecosystems; CREAMS: a system for evaluating best management practices.