Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted...

OBJECTIVE The present study aimed to assess the nitrogen (N) use efficiency of acidified pig slurry for regrowth yield and its environmental impacts on perennial ryegrass swards. METHODS The pH of digested pig slurry was adjusted to 5.0 or 7.0 by the addition of sulfuric acid and untreated as a control. The pig slurry urea of each treatment was labeled with 15N urea and applied at a rate of 2...

Dent corn Andisol at the Hokkaido University Shizunai Livestock Experimental Farm actively emits nitrous oxide (N2O). In order to screen for culturable and active N2O emitters with high N2O emission potential, soft gel medium containing excess KNO3 was inoculated with soil suspensions from farm soil samples collected at different land managements. Dominant bacterial colonies were searched for a...

Organic soils are an important source of N2O, but global estimates of these fluxes remain uncertain because measurements are sparse. We tested the hypothesis that N2O fluxes can be predicted from estimates of mineral nitrogen input, calculated from readily-available measurements of CO2 flux and soil C/N ratio. From studies of organic soils throughout the world, we compiled a data set of annual ...

Our purpose was to measure simultaneous fluxes from soil of both N2O and N2 from the same plot in the field using the 15N-gas "nonequilibrium" technique (i.e., the "Hauck" technique) as used previously for N2. We accommodated analysis of N2O by modifying the head amplifier of our mass spectrometer. Our system accurately measured the 15N enrichments of labeled soil slurries for both N2 and N2O. ...

Nitrite (NO2 ) can accumulate during nitrification in soil following fertilizer application. While the role of NO2 as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil-to-atmosphere fluxes as a function of NO2 levels under aerobic conditions. The current study investigated these kinetics as influe...

Greenhouse gas (GHG) emissions from agroecosystems, particularly nitrous oxide (N2O), are an increasing concern. To quantify N2O emissions from agroecosystems, which occur as a result of nitrogen (N) cycling, a new physically-based routine was developed for the Soil and Water Assessment Tool (SWAT) model to predict N2O flux during denitrification and an existing nitrification routine was modifi...

Nitrous oxide is a greenhouse gas with a global warming potential about 300 times higher than CO2. The main sources of N2O are microbial-mediated nitrogen transformation reactions in soils. Denitrification represents one of the major N2Oproducing pathways in oxygen-limited zones. Soil biochar amendment has been demonstrated to reduce N2O emissions in microcosms and in the field. Although N2O em...

In the last decade, an increasing number of studies have reported that soil nitrous oxide (N2O) emissions can be reduced by adding biochar. However, the effect of biochar amendment on soil N2O emissions during freeze-thaw cycle (FTC) is still unknown. In this laboratory study, biochar (0%, 2% and 4%, w/w) was added into a cultivated sandy loam soil and then treated with 15 times of FTC (each FT...

The use of stable isotopes of N and O in N2O has been proposed as a way to better constrain the global budget of atmospheric N2O and to better understand the relative contributions of the main microbial processes (nitrification and denitrification) responsible for N2O formation in soil. This study compared the isotopic composition of N2O emitted from soils under different tree species in the Br...