Use of Aluminum Chloride to Reduce Ammonia and Greenhouse Gas Emissions from Beef Pen Surface Material

Pen surface amendments are a tool that beef producers can use to reduce emissions and increase nutrient retention in manure. Previous studies demonstrated that aluminum sulfate (alum) could effectively lower ammonia (NH3) emissions but caused increased sulfide emissions. An alternative to alum is aluminum chloride (AlCl3). The objective of this study was to determine if the addition of AlCl3 to beef pen surface material (PSM) could lower NH3 losses while also lowering CO2, N2O and CH4 emissions. Aluminum chloride was added to pans containing 3 kg of PSM and 3 kg of water at a rate of 0%, 2.5%, 5%, and 10% (g g(-1) as-is) of the PSM mass, and emissions were measured for 21 days. The addition of AlCl3 to PSM lowered (p < 0.01) the pH to 5.8-7.2 compared to untreated PSM (8.2). Nitrogen and sulfur content of the PSM was not affected by AlCl3 treatment (p >= 0.14). Cumulative NH3 emissions decreased (p < 0.01) as AlCl3 inclusion increased and were 87.3, 60.5, 33.0, and 20.2 kg ha-1 for the 0%, 2.5%, 5%, and 10% AlCl3 treated PSM, respectively. Cumulative CO2, CH4, and N2O emissions also decreased linearly as the inclusion rate of AlCl3 increased. Aluminum chloride appears to be a promising option for beef feedlot producers to reduce emissions from the pen surface.