Factors Affecting Greenhouse Gas Emissions from Beef Cattle Feedyard Manure: A Laboratory Study.

Improved predictive models for nitrous oxide (N₂O) and methane (CH₄) are crucial for assessing the greenhouse gas (GHG) footprint of beef cattle production. Biochemical process-based models to predict GHG from manure rely on information derived from studies on soil and only limited study has been conducted on manure GHG. Little is known about specific factors that drive production and volatilization of N₂O and CH₄ from feedyard manure. Preliminary studies are underway under controlled laboratory incubations with feedyard manure and soil. The objectives of this study are to evaluate effects of water content, urea concentration, C:N ratio, temperature, and other factors on N₂O, CH₄, carbon dioxide (CO₂) and ammonia (NH₃) emissions from manure, and compare these results to those obtained from agricultural soil. In addition, this work will evaluate the efficacy of methods to mitigate GHG and NH₃ emissions (e.g., urease and nitrification inhibitors, zeolite) from feedyard manure.