Field Measurements of Nitrous Oxide Emissions across a Nitrogen Fertilizer Gradient for Corn Cropping Systems.
John P. Hoben, R.J. Gehl, and G.P. Robertson. Crop and Soil Sciences, Michigan State University, 584 PSSB, East Lansing, MI 48824
Significant reductions in nitrous oxide (N2O) emissions from agricultural land in corn (Zea maize L.) cropping systems may be possible by reducing N fertilizer inputs with relatively little impact on crop grain yield or economic return. To test this hypothesis, experiments were conducted at 4 locations currently in corn production in Michigan in 2007. All sites were under a corn-soybean rotation. Prior to planting, six rates of urea fertilizer (0-225 kg ha-1) were broadcast and incorporated into four replicate plots (RCBD) at each of the sites. Field measurements at each site included N2O emission via static chambers, soil temperature, soil moisture, soil inorganic nitrogen (0-10 cm), and corn grain yield. Measurements were taken immediately prior to fertilization then on a 7-10 day frequency throughout the growing season. Additional measurements were collected immediately following fertilization and rain events at the frequency of every 2-3 days.