Submitted to: Journal of Soil and Water Conservation
Publication Type: Abstract Only
Publication Acceptance Date: May 5, 2008
Publication Date: August 12, 2008
Citation: Halvorson, A.D., Del Grosso, S.J., Reule, C.A. 2008. Management Effects On Nitrous Oxide Emissions From Irrigated Cropping Systems. Soil and Water Conservation Society meeting. July 26-30, 2008. On-line Conference abstract. Book, p. 52. Technical Abstract: The effects of N fertilization and irrigated crop management practices on nitrous oxide (N2O) emissions were measured. Emissions were monitored from irrigated conventional-till (CT) continuous corn (CC) (CT-CC) and no-till (NT) CC (NT-CC) cropping systems receiving N fertilizer rates (0, 67, 134, and 246 kg N/ha) during the 2006 growing season and N rates of 0 and 246 kg N/ha during the 2007 growing season. In 2006, a polymer-coated urea (PCU) was applied at half the N rate at corn emergence and half as dry urea in mid-June, both banded on the soil surface in the corn row followed by irrigation. In 2007, PCU and urea were applied at corn emergence to separate plots in the CT-CC and NT-CC systems. N2O fluxes were measured during the growing season using static, vented chambers, one to three times per week, and a gas chromatograph analyzer. Linear increases in N2O emissions were observed with increasing N-fertilizer rate in 2006. In 2006 and 2007, N2O emissions were greater from CT-CC than from NT-CC. Application of PCU resulted in significant reduction in N2O emissions in the NT-CC system in 2007 compared with urea. Spikes in N2O emissions following N fertilizer application were greater with urea than with PCU. The PCU fertilizer N source showed potential for reducing N2O emissions from irrigated cropping systems in 2007. The 2007 results indicate that N sources need to be evaluated further to determine their value in reducing N2O emissions in cropping systems.