Submitted to: Soil Science Society of America Journal
Publication Type: Abstract Only
Publication Acceptance Date: August 16, 2000
Publication Date: N/A
Technical Abstract: Ammonia loss accounts for much of the gaseous nitrogen loss from a feedlot; however, denitrification has not been thoroughly investigated for a feedlot soil environment. The objectives of this study were to determine the seasonal denitrification enzyme activity (DEA) of a feedlot soil and explain potential controlling mechanisms. Three locations were identified as having varying levels of microbial activity using electromagnetic induction mapping techniques. Three depths (unconsolidated surface soil, 0 - 10 cm, 10 - 20 cm) were isolated at each location and analyzed for DEA, nitrification activity, denitrifier most probable number, soil moisture, and pH. Denitrification enzyme activity varied from 0.0 to 132.2 mmol/gdw/hr based on season, depth, and location within the feedlot. However, no single factor correlated with DEA across all locations and depths. The DEA of the unconsolidated surface soil furthest from the feedbunk maintained the highest level of all locations and depths, even when soil temperatures were near freezing and soil was dry. The relative DEA below 10 cm for all locations was very low during the entire investigation.