Nitrogen source effects on soil nitrous oxide emissions from strip-till corn.
Nitrogen (N) application to crops generally results in increased nitrous oxide (NO) emissions. Commercially available, enhanced-efficiency 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 strip-till (ST) corn ( L.) production system. Enhanced-efficiency N fertilizers evaluated were a controlled-release, polymer-coated urea (ESN), stabilized urea, and UAN products containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus), and UAN containing a slow-release N source (Nfusion). Each N source was surface-band applied (202 kg N ha) at corn emergence and watered into the soil the next day. A subsurface-band ESN treatment was included. Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. All N sources had significantly lower growing season NO emissions than granular urea, with UAN+AgrotainPlus and UAN+Nfusion having lower emissions than UAN. Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Loss of NO-N per kilogram of N applied was <0.8% for all N sources. Corn grain yields were not different among N sources but greater than treatments with no N applied. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in strip-till, irrigated corn in semiarid areas.
USDA-ARS, Fort Collins, CO, USA. ardell.halvorson@ars.usda.gov
Ardell D
AD
Halvorson
Stephen J
SJ
Del Grosso
Claudia Pozzi
CP
Jantalia
D000383:Agriculture / Q000379:methods*; D000393:Air Pollutants / Q000737:chemistry*; D000818:Animals; D002245:Carbon Dioxide; D008697:Methane; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism; D009609:Nitrous Oxide / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D013997:Time Factors; D003313:Zea mays / Q000254:growth & development / Q000378:metabolism
D000393:Air Pollutants; D012987:Soil; D002245:Carbon Dioxide; D009609:Nitrous Oxide; D009584:Nitrogen; D008697:Methane