Determination of Ammonia and Greenhouse Gas Emissions from Land Application of Swine Slurry: A Comparison of Three Application Methods.

Authors: Lovanh, Nanh; Warren, Jason; Sistani, Karamat

Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2009
Publication Date: 10/23/2009
Citation: Lovanh, N.C., Warren, J.G., Sistani, K.R. 2009. Determination of Ammonia and Greenhouse Gas Emissions from Land Application of Swine Slurry: A Comparison of Three Application Methods. Bioresource Technology. 101:1662–1667.

Interpretive Summary: The traditional practice of land application using animal liquid manure for fertilization purpose is by spraying. This method can lead to major losses of essential nutrients for crops such as nitrogen and carbon compounds. This technique can also create a major emission problem in dispersing malodorous and other gaseous compounds in the air (i.e., ammonia and greenhouse gases such as methane and carbon dioxide). In this study, we monitored the initial greenhouse gases emission using flux chamber and gas analyzer from three different liquid manure application methods at a farm in Larue County, KY. Swine slurry was applied to a farm land that was divided into subplots. Row injection, surface spray, and aerway injection were utilized to apply the slurry. Ammonia and greenhouse gas (GHG) concentrations such as methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) were monitored using a photoacoustic gas analyzer. Ammonia and GHG concentrations were monitored immediately after application, 72 and 216 hours after application. The results showed that surface spray produced the greatest initial ammonia, methane, nitrous oxide, and carbon dioxide fluxes. However, the aerway injection method seemed to create the highest gas (GHG) concentrations inside the monitoring chambers at the initial application and produced the highest gas fluxes at subsequent sampling time (e.g., 72 hrs after application). Nevertheless, surface spray method appeared to produce the highest gas fluxes, and row injection method appeared to emit the least amount of greenhouse gases into the atmosphere. Gas fluxes decreased over time and did not depend on the initial headspace concentration in the monitoring flux chambers.

Technical Abstract: The traditional practice of land application using animal liquid manure for fertilization purpose is by spraying. This method can lead to major losses of essential nutrients for crops such as nitrogen and carbon compounds. This technique can also create a major emission problem in dispersing malodorous and other gaseous compounds in the air (i.e., ammonia and greenhouse gases such as methane and carbon dioxide). In this study, we monitored the initial greenhouse gases emission using flux chamber and gas analyzer from three different liquid manure application methods at a farm in Larue County, KY. Swine slurry was applied to a farm land that was divided into subplots. Row injection, surface spray, and aerway injection were utilized to apply the slurry. Flux chambers were deployed at different application plots. Ammonia and greenhouse gas (GHG) concentrations such as methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) were monitored using a photoacoustic gas analyzer. Ammonia and GHG concentrations were monitored immediately after application, 72 and 216 hours after application. The concentrations were measured every half an hour (broken down into 10-minute periods) with half an hour allocation for equilibrium with the atmospheric conditions between sampling. Gas fluxes were calculated based on Fickian diffusion. Comparison of linear and non-linear regression of calculating gas fluxes was carried out. Linear regression resulted in smaller fluxes. The results showed that the initial ammonia flux ranged from 5.80 mg m-2 hr-1 for surface spray method to 1.80 mg m-2 hr-1 for row injection method. The initial fluxes of methane ranged from 8.75 mg m-2 hr-1 for surface spray to 2.27 mg m-2 hr-1 for aerway injection, carbon dioxide ranged from 4357 mg m-2 hr-1 for surface spray to 60 mg m-2 hr-1 for row injection, and nitrous oxide ranged from 0.89 mg m-2 hr-1 for surface spray to 0.22 mg m-2 hr-1 for row injection. However, the aerway injection method seemed to create the highest gas (GHG) concentrations inside the monitoring chambers at the initial application and produced the highest gas fluxes at subsequent sampling time (e.g., 72 hrs after application). Nevertheless, surface spray method appeared to produce the highest gas fluxes, and row injection method appeared to emit the least amount of greenhouse gases into the atmosphere. Gas fluxes decreased over time and did not depend on the initial headspace concentration in the monitoring flux chambers.