Gaseous emissions (NH₃, N₂O and CH₄) following manure or urea application to soil as influenced by amendments
Sonthi, R. K. (2010). Gaseous emissions (NH₃, N₂O and CH₄) following manure or urea application to soil as influenced by amendments (Thesis, Master of Philosophy (MPhil)). University of Waikato, Hamilton, New Zealand. Retrieved from http://hdl.handle.net/10289/5144
Permanent Research Commons link: http://hdl.handle.net/10289/5144
Increasing concentrations of greenhouse gases in the atmosphere may contribute to global warming. The three most important greenhouse gases are carbon dioxide (mainly from burning fossil fuels and deforestation), methane (mainly from ruminant animals and waste management) and nitrous oxide (mainly from dung, urine, and nitrogenous fertilisers). Dairy farms contribute to greenhouse gas emissions because of nitrous oxide and methane emissions (Whitehead et al., 2009). Herd-homes or stand-off pads are increasingly used on dairy farms to minimise soil pugging and compaction. The manure collected from herd-home bunkers or stand-off pads, may be a source of gaseous emissions (NH₃, N₂O and CH₄). Addition of soil or sawdust to manure prior to land application of manure is a potential best farm management practice to minimise gaseous losses. The specific objectives of the study were to: 1. Determine the optimum flow rate for measurement of ammonia emissions from manure or urea application to soil using a chamber method. 2. Quantify gaseous (NH₃, N₂O and CH₄) emissions from manure or urea after application to soil. 3. Determine the effects of addition of soil or sawdust to manure prior to land application of manure on subsequent gaseous emissions. 4. Determine the effects of surface or incorporated land application of manure or urea on gaseous emissions. A preliminary experiment was undertaken to determine the optimum flow rate to measure ammonia emissions, from manure or urea after application to soil, using a chamber method. The flow rate experiment was set up in the glasshouse with 3 replications of 9 flow rate treatments. A flow rate of 5 L min-¹ (1 exchange volume min-¹) was determined as the optimum air flow rate to use in the chamber method to measure ammonia volatilisation. An experiment was undertaken, with 27 pots and 3 replications of 9 treatments, to investigate the effect of soil or sawdust addition to manure on gaseous emissions (NH₃, N₂O and CH₄), when applied on the land surface or incorporated. The physical and chemical properties of the soil, urine, dung, and sawdust were determined in the laboratory. Addition of sawdust was more effective in reducing ammonia emissions, than addition of soil, to manure prior to land application. The incorporated application of all manure treatments resulted in less NH₃ volatilisation compared to surface application. Total ammonia losses were 51% of the applied N from the surface application and 2% of the applied N from incorporated application of urine and dung with soil, and 15% of the applied N from the surface application and 4% of the applied N from incorporated application of urine and dung with sawdust. Ammonia emissions followed a general pattern of rapid emission on day 2 after the application of the urine and dung to soil followed by a progressive decline over time for both the surface and incorporated application for all the manure treatments applied. Total N₂O loss of 14% of applied N was observed with incorporated application of manure with sawdust. Most treatments had no net methane emission. Addition of soil and sawdust to manure, prior to application to soil, reduced ammonia emissions and increased nitrous oxide emissions.
University of Waikato
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