Technical Abstract: Crop and soil management affect seedbank inputs and outputs of summer annual weeds. Inputs are governed primarily by in situ seed production, and seed germination is one of the most important outputs. We have studied effects of management and weather variables on seed production and germination/emergence of several weed species for several years, but emphasize those for Setaria faberi and related species in this report. Ecological information that aided in objective and economically sound management of seedbanks of this species included (1) depth distributions of seeds under various tillage systems, (2) depth-specific maximum emergence potentials, (3) micro-climate inducement of secondary dormancy, (4) timing of seedling emergence, and (5) seedbank recruitment, which is primarily seed production of weeds that escaped control. Integration of these types of relationships into bioeconomic weed/crop management expert systems, like WEEDSIM, provides users with important information not previously available. The enhanced decision-making ability provided by this information can be illustrated with fundamental aspects of seedbank management, such as the decision to till the soil. The tillage decision should be primarily a function of the density of nondormant seeds in the emergence zone and the cost of the tillage operation.