Nanh Lovanh, Jason Warren, and Karamat Sistani. USDA-ARS-AWMRU, 230 Bennett Lane, Bowling Green, KY 42104
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., skatole 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 (100 m by 300 m) that was divided into subplots. Row injection, surface spray, and aerway injection were utilized to apply the slurry. Flux chambers (1 x 4 x 0.5 ft) were deployed at different application plots. Greenhouse gases (GHG) concentrations such as methane, nitrous oxide, and carbon dioxide were monitored using a photoacoustic gas analyzer (CAI, CA). GHG concentrations were monitored for the first four hours of application. The concentrations were measured every half an hour with half an hour allocation for equilibrium with the atmospheric conditions. Two fans were used in the flux chamber for thorough mixing of gases before and during sampling. The results showed that the concentrations of CH4, N2O, and CO2 were 2.04, 1.40, and 980 ppmv, respectively, for row injection. For surface spray, the concentrations were 7.86, 1.9, and 1730 ppmv for methane, nitrous oxide, and carbon dioxide, respectively. The aerway method emitted on average about 13.1, 2.3, 2500 ppmv for CH4, N2O, and CO2, respectively. Thus, the row injection method appears to emit the least amount of greenhouse gases into the atmosphere.