title: Nitrogen source and placement effects on soil nitrous oxide emissions from no-till corn.
abstract: A nitrogen (N) source comparison study was conducted to further evaluate the effects of inorganic N source and placement on growing-season and non-crop period soil nitrous oxide (NO). Commercially available controlled-release N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn ( L.) production system. Controlled-release N fertilizers evaluated were: a polymer-coated urea (ESN), stabilized urea (SuperU), and UAN+AgrotainPlus (SuperU and AgrotainPlus contain nitrification and urease inhibitors). Each N source was surface band applied (202 kg N ha) near the corn row at emergence and watered into the soil the next day. Subsurface banded ESN (ESNssb) and check (no N applied) treatments were included. Nitrous oxide fluxes were measured during two growing seasons and after harvest using static, vented chambers. All N sources had significantly lower growing-season NO emissions than granular urea (0.7% of applied N), with UAN+AgrotainPlus (0.2% of applied N) and ESN (0.3% of applied N) having lower emissions than UAN (0.4% of applied N). Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Corn grain yields were not different among N sources but were greater than the check. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in NT, irrigated corn in semiarid areas. In our study, UAN+AgrotainPlus consistently had the lowest level of NO emissions with no yield loss.
authors.affiliation: USDA-ARS, Fort Collins, CO, USA. ardell.halvorson@ars.usda.gov
authors.forename: Ardell D
authors.initials: AD
authors.lastname: Halvorson
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Del Grosso
mesh_terms: D000383:Agriculture / Q000379:methods*; D018533:Biomass; D002245:Carbon Dioxide / Q000032:analysis; D005308:Fertilizers; D008697:Methane / Q000032:analysis; D009584:Nitrogen / Q000008:administration & dosage* / Q000378:metabolism; D009609:Nitrous Oxide / Q000032:analysis*; D003313:Zea mays / Q000254:growth & development* / Q000378:metabolism
chemical_list: D005308:Fertilizers; D002245:Carbon Dioxide; D009609:Nitrous Oxide; D009584:Nitrogen; D008697:Methane