Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2004
Publication Date: 10/31/2004
Citation: Mosier, A.R., Halvorson, A.D., Reule, C.A., Liu, X.J. 2004. Impact of tillage and n-fertilization on trace gas exchange in irrigated corn in northeastern colorado. American Society of Agronomy Abstracts. CD-ROM.
Technical Abstract: A study was initiated in 1999 to investigate the potential of no-till cropping systems to sequester CO2 while maintaining crop productivity in irrigated agriculture in northeastern Colorado. The impact of agricultural management changes on trace gas fluxes is not well understood. Therefore, we have measured the soil-atmosphere exchange of CO2, CH4 and N2O since the spring of 2002. Fluxes were measured, using vented chambers, one to three times per week, year round, within plots that were continuously cropped to corn under conventional plow tillage (CT), and within no-till continuous corn plots (NT). Nitric oxide fluxes were measured using dynamic chambers in 2003 and 2004. Plots were fertilized at planting in late April with rates of 0 to 224 kg N ha-1 and corn was harvested in November each year. Methane fluxes were small and did not differ between tillage systems. Fluxes were slightly positive in 2002 and slightly negative in 2003, with the difference between years likely due to weather and irrigation intensity with dry soil conditions at planting in 2002 and wet in 2003. N2O fluxes increased linearly with N-fertilizer rate in both years although emission rates were much higher in 2003 than in 2002. In 2002 and 2003, the increase in N2O-N emitted per kg ha-1 of fertilizer N added was 4.42 and 14.6 g ha-1 for CT-CC and 3.14 and 11.4 g ha-1 for NT-CC, respectively. In both years, NO and N2O fluxes were significantly higher in CT compared to NT.