ARS | Publication request: TILLAGE AND NITROGEN APPLICATION EFFECTS ON NITROUS AND NITRIC OXIDE EMISSIONS FROM IRRIGATED CORN FIELDS.

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 2, 2005
Publication Date: November 28, 2005
Citation: Liu, X.J., Mosier, A.R., Halvorson, A.D., Zhang, F.S. 2005. Tillage and nitrogen application effects on nitrous and nitric oxide emissions from irrigated corn fields. Plant and Soil Journal. 276:235-249.

Interpretive Summary: Agricultural soils are sources and sinks for the atmospheric greenhouse gas nitrous oxide (N2O) and the atmospheric oxidant nitric oxide (NO). Soil management through tillage and fertilization potentially can play an important role in minimizing the emission of these gases from the soil to the atmosphere. The influence of tillage and fertilizer application rate on N2O and NO were investigated in a field study during a two year period. Generally, no-till (NT) reduced NO emissions significantly but did not affect N2O emissions compared with conventional tillage (CT) when averaged over two corn seasons. N2O and NO emissions increased linearly with N application rate under both CT and NT. Change of climate and soil conditions (e.g. moist and temperature) explained the emission patterns of N2O and NO as well as their emission ratios under different tillage systems and in different years. Results reveal potential of NT to reduce NO emission without increasing in N2O emission under continuous irrigated corn cropping compared to CT.

Technical Abstract: A 2-yr study was conducted to investigate the potential of no-till cropping systems to reduce N2O and NO emissions under different N application rates in an irrigated cornfield in northeastern Colorado. Flux measurements were begun in the spring of 2003, using vented (N2O) and dynamic (NO) chambers, one to three times per week, year round, within plots that were cropped continuously to corn (Zea mays L.) under conventional-till (CT) and no-till (NT). Plots were fertilized at planting in late April with rates of 0, 134 and 224 kg N ha-1 and corn was harvested in late October or early November each year. N2O and NO fluxes increased linearly with N application rate in both years. Compared with CT, NT significantly reduced emissions of N2O in 2003 and NO in both years but did not significantly affect emission of N2O in 2004. In 2003 and 2004 corn growing seasons, the increase in N2O-N emitted per kg ha-1 of fertilizer N added was 14.5 and 4.1 g ha-1 for CT, and 11.2 and 5.5 g ha-1 for NT, respectively. However, the increase in NO-N emitted per kg ha-1 of fertilizer N added was only 3.6 and 7.4 g ha-1 for CT and 1.6 and 2.0 g ha-1 for NT in 2003 and 2004, respectively. In the fallow season (November 2003 to April 2004), much greater N2O (2.0-3.1 times) and NO (13.1-16.8 times) were emitted from CT than from NT although previous N application did not show obvious carry-over effect on both gas emissions. Results reveal that NT has potential to reduce NO emission without an increase in N2O emission under continuous irrigated corn cropping compared to CT.