Dissolved organic carbon (DOC) as an energy source for denitrifying bacteria has not been consistently accounted for in soil profile nitrogen transformation budgets. While DOC quantity has been attributed as a limiting factor for subsurface denitrification, little is known regarding the bioavailability of DOC for this process. Nutrient management practices may affect leached DOC quantity, but fertilization effect on quality is unknown. The objective of this study was to determine the utilization of leached DOC for denitrification. Soils were collected from the following three treatments of an ongoing, tile drainage field study: (1) corn-corn rotation/fall application of swine manure, (2) corn-corn rotation/spring application of 28% UAN at 178 kg ha^-1, and (3) prairie grass/no fertilizer application. Surface (0-30 cm) soil was collected from plots in late November, 2004 and packed into soil columns of similar bulk density (~1.3 g cm^-3). Six discrete leaching events of 250 mL DI water were conducted over 20 days; leachate was collected and frozen until analysis. Denitrification potential of the DOC was determined by incubation of 50g of subsurface (90-120 cm) soil with 50 mL of leachate for 12 days at 20^oC. Denitrification potential was determined on day 3, 6, 9, and 12. Selected samples were spiked after day 6 with glucose or nitrate to evaluate limiting conditions. DOC concentrations in leachate ranged from 5 to 28 mg-OC L^-1 and were significantly different between events but not between treatments. Preliminary results indicate that subsurface soils are responsive to glucose-C concentrations as low as 5 mg-OC L^-1. Quality effects of leached DOC are inconclusive at this time.