Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 3, 2009
Publication Date: N/A
Technical Abstract: Nitrous oxide emissions were monitored from irrigated corn production systems receiving different N sources at fertilizer rates of 246 kg N ha-1 when in corn (Zea mays L.), 56 kg N ha-1 when in dry bean (Phaseolus vulgaris L.), and 157 kg N ha-1 when in barley (Hordeum distichon L.). Cropping systems included: conventional-till continuous corn (CT-CC); no-till continuous corn (NT-CC); NT corn-dry bean (NT-CDb); and NT corn-barley (NT-CB). In the NT-CC and CT-CC systems, a controlled-release, polymer-coated urea (ESN®) and dry granular urea were compared. In the NT-CDb and NT-CB rotations, a stabilized N source (SuperU®) was compared with urea. Nitrous oxide fluxes were measured one to three times per week during two growing seasons using static, vented chambers and a gas chromatograph analyzer. Cumulative growing season N2O emissions from urea and ESN® application were not different under CT-CC, but were different under NT-CC, where ESN® reduced N2O emissions 49% compared to urea. SuperU® reduced N2O emissions 27% compared to urea with application of 56 kg N ha-1 to dry bean in 2007 and 54% compared to urea with application of 246 kg N ha-1 to corn in 2008 in the NT-CDb rotation. SuperU® reduced N2O emissions 19% compared to urea with application of 157 kg N ha-1 to barley in 2007 and 51% compared to urea with application of 246 kg N ha-1 to corn in 2008 in the NT-CB rotation. This work shows that current tillage and fertilizer N technologies that delay release and transformation of N can substantially reduce N2O emissions from irrigated systems under specific cropping conditions.