Agricultural soils represent the main source of anthropogenic N2O emissions. Recently, interactions of black carbon with the nitrogen cycle have been recognized and the use of biochar is being investigated as a means to reduce N2O emissions. However, the mechanisms of reduction remain unclear. Here we demonstrate the significant impact of biochar on denitrification, with a consistent decrease i...

UNLABELLED Accumulating empirical evidence over the last 60 years has shown that the reduction of N2O to N2 is impaired by low soil pH, suggesting that liming of acid soils may reduce N2O emissions. This option has not gained much momentum in global change research, however, possibly due to limited understanding of why low pH interferes with N2O reductase. We hypothesized that the reason is tha...

UNLABELLED Members of the Fungi convert nitrate (NO3 (-)) and nitrite (NO2 (-)) to gaseous nitrous oxide (N2O) (denitrification), but the fungal contributions to N loss from soil remain uncertain. Cultivation-based methodologies that include antibiotics to selectively assess fungal activities have limitations, and complementary molecular approaches to assign denitrification potential to fungi a...

Soil microorganisms are important sources of the nitrogen trace gases NO and N2O for the atmosphere. Present evidence suggests that autotrophic nitrifiers such as Nitrosomonas europaea are the primary producers of NO and N2O in aerobic soils, whereas denitrifiers such as Pseudomonas spp. or Alcaligenes spp. are responsible for most of the NO and N2O emissions from anaerobic soils. It has been s...

At present, continuous observation data for atmospheric nitrous oxide (N2O) concentrations are still lacking, especially in east Antarctica. In this paper, nitrous oxide background concentrations were measured at Zhongshan Station (69°22'25″S, 76°22'14″E), east Antarctica during the period of 2008-2012, and their interannual and seasonal characteristics were analyzed and discussed. The mean N2O...

Agricultural soils are important sources of atmospheric N2O and CO2. However, in boreal agro-ecosystems the contribution of the winter season to annual emissions of these gases has rarely been determined. In this study, soil N2O and CO2 fluxes were measured for 6 years in a corn-soybean-wheat rotation in northeast China to quantify the contribution of wintertime N2O and CO2 fluxes to annual emi...

Row-crop agriculture is a major source of nitrous oxide (N2O) globally, and results from recent field experiments suggest that significant decreases in N2O emissions may be possible by decreasing nitrogen (N) fertilizer inputs without affecting economic return from grain yield. We tested this hypothesis on five commercially farmed fields in Michigan, USA planted with corn in 2007 and 2008. Six ...

Oceanic oxygen minimum zones are strong sources of the potent greenhouse gas N2O but its microbial source is unclear. We characterized an exponential response in N2O production to decreasing oxygen between 1 and 30 μmol O2 l-1 within and below the oxycline using 15NO2-, a relationship that held along a 550 km offshore transect in the North Pacific. Differences in the overall magnitude of N2O pr...

In Europe agriculture is an important contributor to emissions of the acidifying compound ammonia (NH3) and the greenhouse gases nitrous oxide (N2O) and methane (CH4). Measures to reduce one of these gases may also have an impact on emissions of the others. This study investigates the effects of control options for NH3, N2O, and CH4 that are available for the European agriculture on the emissio...

EXTENDED ABSTRACT Nowadays, biological nutrient removal (BNR) processes have been applied widely for wastewater treatment. However, one type of greenhouse gases, nitrous oxide (N2O), can be released from both nitrification and denitrification during BNR. In our previous study, we found that N2O emission during nitrification could be affected by heterotrophic activities significantly in a BNR sy...