Effects of Manure Storage Additives on Manure Composition and Greenhouse Gas and Ammonia Emissions
Storage of dairy manure slurry allows flexibility in the timing of land application of manure to reduce environmental impacts related to water quality. However, manure storage can increase greenhouse gas (GHG) and ammonia (NH3) emissions and cause operational issues due to the buildup of slurry solids. To combat these negative consequences, stored manure was treated with manure additives, i.e., More than Manure (MTM), Pro-Act Biotech (Pro-Act), and biochar, to quantify their effects on manure solids, nitrogen losses, and GHG emissions in two separate trails. Gaseous emissions were studied over a 48-day manure storage period with treatments of MTM, Pro-Act, aeration and Pro-Act, aeration alone, and biochar. Manure characteristics were further examined in a 28-day manure storage study with treatments of MTM at the supplier-recommended rate, MTM at 25× the recommended rate, aeration and Pro-Act at the supplier-recommended rate, aeration and Pro-Act at 10× the recommended rate, aeration alone, and two additional Pro-Act treatments without aeration, one at the recommended rate and one at 10× that rate. Biochar was the only manure treatment to impact manure characteristics, with significantly more ammoniacal nitrogen (TAN) on day 14 than the control (p < 0.012) in the manure composition study. Biochar did not reduce NH3 emissions from the control, likely due to the 10 cm natural crust on the control. MTM increased CO2 emissions, with significantly higher emissions on days 7 and 14 during the gaseous emissions study. Overall, no treatments were able to reduce manure solids or nitrogen emissions for these manure storage conditions.
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