Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions
Liquid manure storages are an important source of greenhouse gases (GHG) on dairy farms. Methane (CH4) and nitrous oxide (N2O) are the predominant GHGs, while ammonia (NH3) is an indirect source of N2O. Addition of acid to manure has shown promising emission reductions, however, cost of acidificatio...
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Frontiers Media S.A.
2020-10-01
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| Series: | Frontiers in Sustainable Food Systems |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fsufs.2020.568648/full |
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| author | Vera Sokolov Vera Sokolov Andrew VanderZaag Jemaneh Habtewold Kari Dunfield James T. Tambong Claudia Wagner-Riddle Jason J. Venkiteswaran Robert Gordon |
| author_facet | Vera Sokolov Vera Sokolov Andrew VanderZaag Jemaneh Habtewold Kari Dunfield James T. Tambong Claudia Wagner-Riddle Jason J. Venkiteswaran Robert Gordon |
| author_sort | Vera Sokolov |
| collection | DOAJ |
| description | Liquid manure storages are an important source of greenhouse gases (GHG) on dairy farms. Methane (CH4) and nitrous oxide (N2O) are the predominant GHGs, while ammonia (NH3) is an indirect source of N2O. Addition of acid to manure has shown promising emission reductions, however, cost of acidification may be unfeasible for farmers. Fully cleaning storages has also shown to reduce CH4, due to removal of inoculating effects of residual manure (“inoculum”) on fresh manure (FM). However, complete removal of inoculum is practically impossible on large farms, thus acidifying only the inoculum may reduce GHGs without requiring acidification of all FM. This study aimed to quantify the effect of acidified inoculum on CH4, N2O, and NH3 emissions from stored manure and quantify the changes in methanogen abundance and activity. Emissions were measured from six 10.6 m3 storages filled with 20% inoculum (1-year-old manure) and 80% FM. Inoculum was treated in three ways: untreated (control); previously acidified (1-year prior); and newly acidified with 70% H2SO4 (1.1 L m−3 manure). The CH4 and N2O emissions were continuously measured from June—November using tunable diode trace gas analyzers coupled with venturi air flow systems. The NH3 emissions were measured at 24-h intervals 3 × weekly using acid traps. The activity and abundance of methanogens were quantified by targeting the Methyl Coenzyme M Reductase A (mcrA) gene and transcript which encodes a subunit of the key enzyme that catalyzes the final step of methanogenesis. Bacterial abundance was quantified by targeting the bacterial 16S rRNA gene. Quantifications were performed using quantitative real-time PCR. CH4 emissions were reduced by 77% using newly acidified inoculum and 38% using previously acidified inoculum, compared to the control with untreated inoculum (36.1 g CH4 m−2). Significant treatment reductions in mcrA gene and transcript abundance suggest that CH4 reductions were caused by disruption of methanogen activity. NH3 and N2O emissions were reduced by 33 and 73% using acidified inoculum and 23 and 50% using previously acidified inoculum, respectively, compared to the control. Results suggest that lower acid rates and acidifying less frequently may still have good treatment effects while minimizing cost. |
| first_indexed | 2024-12-21T05:23:52Z |
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| id | doaj.art-2101de87e73349f0b3f7d5e2f9ed3fd9 |
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| issn | 2571-581X |
| language | English |
| last_indexed | 2024-12-21T05:23:52Z |
| publishDate | 2020-10-01 |
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| spelling | doaj.art-2101de87e73349f0b3f7d5e2f9ed3fd92022-12-21T19:14:44ZengFrontiers Media S.A.Frontiers in Sustainable Food Systems2571-581X2020-10-01410.3389/fsufs.2020.568648568648Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas EmissionsVera Sokolov0Vera Sokolov1Andrew VanderZaag2Jemaneh Habtewold3Kari Dunfield4James T. Tambong5Claudia Wagner-Riddle6Jason J. Venkiteswaran7Robert Gordon8Department of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, ON, CanadaAgriculture and Agri-Food Canada, Ottawa, ON, CanadaAgriculture and Agri-Food Canada, Ottawa, ON, CanadaAgriculture and Agri-Food Canada, Ottawa, ON, CanadaSchool of Environmental Science, University of Guelph, Guelph, ON, CanadaAgriculture and Agri-Food Canada, Ottawa, ON, CanadaSchool of Environmental Science, University of Guelph, Guelph, ON, CanadaDepartment of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, ON, CanadaSchool of the Environment, University of Windsor, Windsor, ON, CanadaLiquid manure storages are an important source of greenhouse gases (GHG) on dairy farms. Methane (CH4) and nitrous oxide (N2O) are the predominant GHGs, while ammonia (NH3) is an indirect source of N2O. Addition of acid to manure has shown promising emission reductions, however, cost of acidification may be unfeasible for farmers. Fully cleaning storages has also shown to reduce CH4, due to removal of inoculating effects of residual manure (“inoculum”) on fresh manure (FM). However, complete removal of inoculum is practically impossible on large farms, thus acidifying only the inoculum may reduce GHGs without requiring acidification of all FM. This study aimed to quantify the effect of acidified inoculum on CH4, N2O, and NH3 emissions from stored manure and quantify the changes in methanogen abundance and activity. Emissions were measured from six 10.6 m3 storages filled with 20% inoculum (1-year-old manure) and 80% FM. Inoculum was treated in three ways: untreated (control); previously acidified (1-year prior); and newly acidified with 70% H2SO4 (1.1 L m−3 manure). The CH4 and N2O emissions were continuously measured from June—November using tunable diode trace gas analyzers coupled with venturi air flow systems. The NH3 emissions were measured at 24-h intervals 3 × weekly using acid traps. The activity and abundance of methanogens were quantified by targeting the Methyl Coenzyme M Reductase A (mcrA) gene and transcript which encodes a subunit of the key enzyme that catalyzes the final step of methanogenesis. Bacterial abundance was quantified by targeting the bacterial 16S rRNA gene. Quantifications were performed using quantitative real-time PCR. CH4 emissions were reduced by 77% using newly acidified inoculum and 38% using previously acidified inoculum, compared to the control with untreated inoculum (36.1 g CH4 m−2). Significant treatment reductions in mcrA gene and transcript abundance suggest that CH4 reductions were caused by disruption of methanogen activity. NH3 and N2O emissions were reduced by 33 and 73% using acidified inoculum and 23 and 50% using previously acidified inoculum, respectively, compared to the control. Results suggest that lower acid rates and acidifying less frequently may still have good treatment effects while minimizing cost.https://www.frontiersin.org/article/10.3389/fsufs.2020.568648/fullmanure managementmethanogensmethaneinoculumacidification |
| spellingShingle | Vera Sokolov Vera Sokolov Andrew VanderZaag Jemaneh Habtewold Kari Dunfield James T. Tambong Claudia Wagner-Riddle Jason J. Venkiteswaran Robert Gordon Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions Frontiers in Sustainable Food Systems manure management methanogens methane inoculum acidification |
| title | Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions |
| title_full | Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions |
| title_fullStr | Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions |
| title_full_unstemmed | Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions |
| title_short | Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions |
| title_sort | acidification of residual manure in liquid dairy manure storages and its effect on greenhouse gas emissions |
| topic | manure management methanogens methane inoculum acidification |
| url | https://www.frontiersin.org/article/10.3389/fsufs.2020.568648/full |
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