Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Late Spring 2013
17 The Fluid Journal Late Spring 2013 Figure 5. Daily N2O -N fluxes with standard error bars at each sampling date in 2010 with for (A) SuperU, urea, ESN, ESN subsurface band (ESNssb), and check; and (B) urea-ammonium nitrate (UAN), UAN+AgrotainPlus (AP), UAN+Nfusion (Nf) and blank. Note the different scales on Y axis. 2013 Fluid Fertilizer Technology Roundup THIS COMING WINTER Watch for more information system, tillage management, and site- specific conditions. The growing season N2O-N emissions from the application of a unit of the enhanced-efficiency N fertilizers used in this study were considerably lower (<0.5%) than the default 1% from Tier 1 methodology used by the IPCC to estimate yearly N2O-N emissions resulting from N fertilizer application. This indicates the need for source and sight-specific N2O emission data. The results presented here may indicate that irrigated soils under semiarid conditions have relatively low N2O -N losses, provided irrigation is well managed to avoid water- logged conditions and potential for denitrification. In only one out of nine years have N2O-N emissions exceeded 1% of N applied at this site with the one year (2003) having very wet soil conditions at fertilization, planting, and during the early growing season. Summing up Controlled-release, slow-release, and stabilized N sources reduced N2O-N emissions from an irrigated ST continuous corn cropping system when compared with granular urea. Nitrous oxide fluxes resulting from urea, UAN, SuperU, UAN+Nfusion, and UAN+AgrotainPlus applications peaked within days after application, whereas N2O flux peaks from ESN and ESNssb occurred 4 to 6 weeks after application but with flux peaks generally of lower magnitude than with conventional urea. All enhanced-efficiency N fertilizers and UAN reduced growing season N2O emissions, when compared with urea and UAN+Nfusion and UAN+AgrotainPlus, did so in comparison to UAN. Nitrification was probably the main pathway of soil N2O loss from applied N fertilizer from this ST, irrigated system throughout
Early Spring 2013