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Transformation of Organic Matter and the Emissions of Methane and Ammonia during Storage of Liquid Manure as Affected by Acidification
Author(s) -
Sommer Sven G.,
Clough Timothy J.,
Balaine Nimlesh,
Hafner Sasha D.,
Cameron Keith C.
Publication year - 2017
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2016.10.0409
Subject(s) - chemistry , nitrous oxide , liquid manure , manure , ammonia , environmental chemistry , carbon dioxide , organic matter , dissolved organic carbon , methane , slurry , nitrogen , greenhouse gas , sulfuric acid , inorganic chemistry , environmental engineering , agronomy , environmental science , ecology , organic chemistry , biology
Acidification of livestock manure can reduce emission of the greenhouse gases methane (CH 4 ) and nitrous oxide (N 2 O), as well as ammonia (NH 3 ). We examined the relation between emission of these gases and transformation of organic matter as affected by acidification. Liquid cattle manure was acidified with sulfuric acid to pH 5.5 at a pilot scale (100 L), and we measured effects on CH 4 , N 2 O, CO 2 and NH 3 emissions and on transformation of pH buffer components and organic matter. Acidification reduced NH 3 emissions by 62% (47 d) and emission of CH 4 by 68% (57 d). Emissions of N 2 O were negligible, probably due to the absence of a surface crust. Reductions in NH 3 and CH 4 emission were highest at the start but declined over time concomitantly with a gradual increase in the stored liquid manure pH. Acidification did not significantly affect CO 2 emissions. Emission of CO 2 was high, five‐ to ten‐fold of CH 4 emissions, until Day 16 of storage, after which the CO 2 emission rate declined to around twice the CH 4 emission rate; consequently, the majority of C loss during the early stages of storage was CO 2 . Cumulative emission of C in CO 2 and CH 4 closely matched depletion of dissolved organic carbon (DOC), suggesting that DOC may be a predictor for CH 4 emission from dilute slurries. volatile fatty acid and total ammoniacal nitrogen concentrations in surface layers were substantially higher than at the center of stored liquid manure, perhaps resulting from microbial activity at the surface. This pattern deserves attention when predicting NH 3 emission from stored slurry. Core Ideas Acidification reduced emission of NH 3 and CH 4 , but the effect diminished over time. Dissolved organic carbon may be a predictor for greenhouse gas emission. The majority of carbon loss during the early stages of storage was as CO 2 . VFA and TAN concentrations in surface layers may be higher than at the center.