ARS | Publication request: Impact of Tillage and Fertilizer Application Method on Gas Emissions in a Corn Cropping System

Submitted to: Pedosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 2012
Publication Date: October 1, 2012
Citation: Smith, K.E., Watts, D.B., Way, T.R., Torbert III, H.A., Prior, S.A. 2012. Impact of Tillage and Fertilizer Application Method on Gas Emissions in a Corn Cropping System. Pedosphere. 22(5):604-615.

Interpretive Summary: Three trace gases (carbon dioxide, nitrous oxide, and methane) coming from agricultural land can potentially contribute to global climate change. Our results suggest that conservation practices (no-till) can significantly reduce CO2 loss. We also found that fertilizer source and its placement can also impact the amount of N2O and CO2 contributing to the overall CO2 equivalents lost. In addition, our systems appeared to be sinks rather than sources of CH4. Taken together, the overall CO2 equivalent loss was not impacted by tillage, but band applied fertilizer and poultry litter increased the CO2 equivalent loss from soil. These results are valuable in that they suggest that fertilizer source and placement can impact greenhouse gas emissions and suggest further research is needed into this important issue.

Technical Abstract: Tillage and fertilization practices used in row crop production are thought to alter greenhouse gas emissions from soil. This study was conducted to determine the impact of fertilizer sources, land management practices, and fertilizer placement methods on greenhouse gas emissions. A new prototype implement for applying poultry litter in subsurface bands in the soil has been developed and this implement was used in this study. The field site was located at the Sand Mountain Research and Extension Center in the Appalachian Plateau region of northeast Alabama on a Hartsells fine sandy loam (fine-loamy, siliceous, subactive, thermic Typic Hapludults). Measurements of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions followed Greenhouse gas Reduction through Agricultural Carbon Enhancement network (GRACEnet) protocols to assess the effects of different tillage (conventional vs. no-tillage) and fertilizer placement (subsurface banding vs. surface application) practices in a corn (Zea mays L.) cropping system. Fertilizer sources were urea-ammonium nitrate (UAN), ammonium nitrate (AN) and poultry litter (M) applied at a rate of 170 kg ha-1 of available N. Banding of fertilizer resulted in the greatest concentration of gaseous loss (CO2 and N2O) compared to surface applications of fertilizer. Fertilizer banding increased CO2 and N2O loss on various sampling days throughout the season with poultry litter banding emitting more gas than UAN banding. Conventional tillage practices also resulted in a higher concentration of CO2 and N2O loss when evaluating tillage by sampling day. Throughout the course of this study, CH4 flux was not affected by tillage, fertilizer source, or fertilizer placement method. These results suggest that poultry litter use and banding practices have the potential to increase greenhouse gas emissions.