The importance of understanding nitrogen use efficiency in bermudagrass systems is increasing because of sewage effluent dispersal. To decrease negative impacts on surface waters, new environmental regulations are limiting direct discharge permits and requiring effluent dispersal on the landscape. As a result, effluent applications on golf courses, athletic fields, and home lawns are on the rise. Nitrogen is the main pollutant of concern in effluent. Experiments using 15N-nitrate are being conducted to determine the fate and the maximum nitrogen loading capacities of bermudagrass systems during growth and dormancy cycles. 15 cm-deep cores are removed from the field and placed into growth chambers in the NCSU Phytotron. Chamber conditions simulate temperature and light in the field, based on 50-year historical climate data. Cores are secured into air-tight fittings that allow a vacuum to be applied for removing excess water and collecting leachate. 15N enriched liquid fertilizer is applied and plants harvested periodically over several weeks. Results indicate that, with moderate application rates, actively growing bermudagrass rapidly takes up and assimilates applied 15N-nitrate. Most accumulates in the shoots (~ 45%), but substantial amounts also accumulate in rhizomes (~ 25%) and roots (~ 20%). A portion is absorbed into the soil microbial fraction (< 10%) and then released within about 10 days and apparently taken-up by the plant. In contrast, with dormant bermudagrass, the majority of applied nitrate remains in solution for an extended period, and thus, can be readily leached through the soil profile.