HR: 0800h
AN: B51A-0181    [Abstracts]
TI: Nitrous Oxide Emissions From Livestock Waste Under Oxic and Anoxic Conditions
AU: * Molodovskaya, M S
EM: mm433@cornell.edu
AF: Cornell University, BEE Department, 76 Riley-Robb Hall, Ithaca, NY 14850
AU: Singurindy, O
EM: os43@cornell.edu
AF: Cornell University, BEE Department, 76 Riley-Robb Hall, Ithaca, NY 14850
AU: Richards, B K
EM: bkr2@cornell.edu
AF: Cornell University, BEE Department, 76 Riley-Robb Hall, Ithaca, NY 14850
AU: Giri, S K
EM: skg29@cornell.edu
AF: Cornell University, BEE Department, 76 Riley-Robb Hall, Ithaca, NY 14850
AU: Steenhuis, T S
EM: tss1@cornell.edu
AF: Cornell University, BEE Department, 76 Riley-Robb Hall, Ithaca, NY 14850
AB: Nitrous oxide (N₂O) gas has been identified as an important contributor to atmospheric greenhouse effect. The largest agricultural N₂O emissions are from fertilizer applications, tillage and livestock on farms. Livestock sources include manure storage, handling, and land application, and N₂O emissions from those manure management practices can be very significant. The development of manure best management practices to minimize the contribution of livestock to the global greenhouse effect requires knowledge of the environmental and atmospheric conditions that affect nitrous oxide emission rates. In this study we estimated nitrous oxide emissions from fresh dairy manure under several air exchange rates creating different oxic and anoxic conditions. During a three weeks period, gas flows with and without oxygen (compressed air and dinitrogen) at different rates were continuously passed through manure samples incubated at 25°C. Nitrogen transformations in manure and N₂O emissions were quantified as a function of flow rate. We found that manure treatments involving exposure to the air could be significant source of nitrogen gaseous emissions. The rates and dynamics of N₂O emissions were substantially impacted by oxygen and total ammoniac nitrogen content, which, in turn, was regulated by the aeration rate. The higher oxygen availability resulted from high aeration significantly enhanced nitrification and inhibited denitrification. Increasing airflow rates led to higher N losses through ammonia volatilization and, consequently, to the faster depletion of total N stock and reducing potential for N₂O formation. N-N₂O losses varied from 1.6 to 4.2% of manure total nitrogen content. The maximum N₂O emissions were observed at moderate aeration rates.
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0469 Nitrogen cycling
DE: 0470 Nutrients and nutrient cycling (4845, 4850)
SC: Biogeosciences [B]
MN: Fall Meeting 2005