Submitted to: Soil Science Society of America Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/15/2010
Publication Date: 1/1/2011
Citation: Omonode, R.A., Vyn, T.J., Smith, D.R., Gal, A. 2011. Nitrous oxide emissions in corn following three decades of tillage and rotation treatments. Soil Science Society of America Journal. 75:152-163. Interpretive Summary: Nitrous oxide, a greenhouse gas, emissions from agricultural activities occurs predominantly from the soil. This study was conducted to determine the effects of cropping systems and tillage on nitrous oxide emissions from agricultural soils in the Midwestern U.S. The cropping systems used were continuous corn, or corn in rotation with soybeans. Tillage systems used were chisel plow, moldboard plow or no-tillage for both cropping systems. Gas emissions were monitored intensely for 168 hr following tillage operations, and seasonal emissions were estimated from several measurements during the growing season. Nitrous oxide emissions were 2.1, 1.3 and 1.3 mg N2O m-2 hr-1 for chisel plow, moldboard plow and no-tillage, respectively. Continuous corn emitted 27% more nitrous oxide than the corn-soybean rotation. The impact of this research is to provide insight to other researchers, modelers, policy makers, and land managers about the potential impact of cropping systems management. For example, these results indicate that continuous corn managed with chisel plow, which may become a predominant cultural practice in Indiana as ethanol plants come online, could be detrimental to air quality due to greater emissions of nitrous oxide.
Technical Abstract: An estimated 94% of the total N2O emissions resulting from agricultural activities in the United States arise from the soil surface. Yet, few research studies have assessed the long-term and possibly interacting effects of the predominant tillage and rotation practices in the Midwestern United States on N2O emissions from the soil surface. This study was conducted in 2004 and 2005 on a tillage and rotation experiment initiated in 1975 on a Chalmers silty clay loam (Typic Endoaquoll) in west-central Indiana. Our objectives were to assess (i) the effects of chisel (CP) and moldboard plow (MP) on soil N2O emissions relative to no-till (NT) and (ii) how N2O emissions are related to environmental and soil variables in corn and corn-soybean rotations. Short-term gas emissions were measured immediately before, and periodically after primary tillage operations for up to 168 hrs. Seasonal emissions were measured at weekly or biweekly intervals for up to 14 weeks in the growing season for corn. Short-term N2O emissions were significantly affected by tillage x rotation interaction. Seasonal emissions were significantly affected by tillage and rotation but not their interaction. Precipitation, air temperature, soil moisture and temperature, soil mineral N, and CO2 emissions significantly influenced N2O emissions and accounted for 52% of the variability of N2O emissions. On average, N2O emissions were 2.09, 1.31, and 1.29 mg m-2 hr-1 respectively, for CP, MP and NT and mean N2O emissions were 27% higher under continuous corn than rotation corn. Our results suggested that long-term CP management in continuous corn would result in higher N2O emissions rates during the growing season than CP management in rotation corn or NT systems in either continuous corn or corn-soybean rotations.