Soil denitrification is considered the most unconstrained process in the global N cycle due to uncertain in situ N2 flux measurements, particularly in natural and semi-natural terrestrial ecosystems. N tracer approaches can provide in situ measurements of both N2 and N2O simultaneously, but their use has been limited to fertilized agroecosystems due to the need for large N additions in order to...

Nitrous oxide (N2O) has 265 times greater greenhouse potential than carbon dioxide and its atmospheric concentration has increased by about 20% since industrialization; however, N2O production and emissions from aquatic systems are poorly constrained. To evaluate N2O fluxes associated with meteoric groundwater discharge to coastal zones, we measured N2O concentrations in May and October 2011 fr...

Forest ecosystems may provide strong sources of nitrous oxide (N2O), which is important for atmospheric chemical and radiative properties. Nonetheless, our understanding of controls on forest N2O emissions is insufficient to narrow current flux estimates, which still are associated with great uncertainties. In this study, we have investigated the quantitative and qualitative relationships betwe...

The nitrous oxide emissions were measured at three tundra sites and one snowpack on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were 1.1+/-2.2 and 0.6+/-1.7 microg N2O m(-2)h(-1), respectively. The average flux from tundra soil site with penguin dropping addition was 3.7+/-2.0 microg N2O m(-2)h(-1), 3-6 times those from...

Rising concentrations of nitrous oxide (N2O) in the atmosphere are causing widespread concern because this trace gas plays a key role in the destruction of stratospheric ozone and it is a strong greenhouse gas. The successful mitigation of N2O emissions requires a solid understanding of the relative importance of all N2O sources and sinks. Stable isotope ratio measurements (δ15N-N2O and δ18O-N2...

Manure fertilization of soil significantly impacts the level of nitrous oxide (N2O) emission. Despite their short duration, periods of significant N2O emissions during soil thaws in winter and spring are an important portion of the total annual emissions from agricultural lands. The goal of this study was to understand the effects of tillage, moisture content and manure application on N2O emiss...

Switchgrass (Panicum virgatum L.) is being evaluated as a bioenergy crop for the northern Great Plains. Field measurements of CO2, CH4, and N2O flux are needed to estimate the net greenhouse gas (GHG) balance of this biofeedstock. The study objective was to determine effects of recommended Nitrogen (N) fertilization (67 kg ha 1 of N applied) and unfertilized switchgrass on growing season soil-a...

Denitrifying polyphosphate accumulating organisms (DNPAOs) are very promising for simultaneous nitrogen and phosphorus removal. While during denitrification, emission of a greenhouse gas, nitrous oxide (N2O), may occur. In this study, DNPAOs were enriched in a lab-scale reactor, and N2O emission was examined under different electron acceptor conditions. During the anoxic phase, with the uptake ...

To gain the effects of N fertilizer applications on N2O emissions and local climate change in fertilized rubber (Hevea brasiliensis) plantations in the tropics, we measured N2O fluxes from fertilized (75 kg N ha(-1) yr(-1)) and unfertilized rubber plantations at Xishuangbanna in southwest China over a 2-year period. The N2O emissions from the fertilized and unfertilized plots were 4.0 and 2.5 k...

Urine excreted by cattle can produce very high concentrations of available N in relatively small volumes of soil and lead to high nitrous oxide (N2O) emissions. Application of the nitrification inhibitor dicyandiamide (DCD) can inhibit nitrification. DCD application results in lower nitrate (NO3 ) concentrations and N2O emissions from denitrification in urine affected soils. However, the effect...