Ammonia and greenhouse gas emissions from beef feedlot surface material treated with aluminum sulfate (alum) or microbial amendments

Abstract

AbstractA lab‐scale study evaluated ammonia (NH3) and greenhouse gases, emissions when aluminum sulfate (alum) or a microbial product were added to beef feedlot surface material (FSM). Three kilograms of FSM and 1.5 kg of water were added to stainless steel pans (50 cm × 30 cm × 6.5 cm). Treatments included a control (no amendment), 450 g alum, or 0.5 g microbial product. The pans were placed in an environmental chamber that was maintained at 23°C and 50%–60% humidity. Emissions were measured three times weekly for 3 weeks. Ammonia, N2O, and CH4 were lower (p < 0.01) from pans with amendments compared to the control pans; emissions from the FSM that received the microbial treatment were lower than the FSM treated with alum. Methane emissions were similar for the control and alum‐treated FSM but lower (p < 0.01) for the FSM that was treated with the microbial product. Nitrate‐N was lower, and NH4+‐N and total sulfur concentrations were higher in FSM treated with alum compared to no treatment or the microbial treatment (p < 0.01). Results indicate that both alum and microbial amendments have benefits in reducing emissions from the feedlot surface, with the microbial product providing additional reductions in emissions compared to the alum.