Additional Index Words: rate constant, zero-order reaction, firstorder reaction, submerged soil, available carbon. A theoretical analysis of denitrification occurring in submerged soil in a test tube, when assumed to be a zero-order reaction with available ———————————————————— organic carbon nonlimiting, appears to be a first-order reaction if the __ , , , , c effects of diffusion are neglected...

Agricultural soils are the primary anthropogenic source of atmospheric nitrous oxide (N2O), contributing to global warming and depletion of stratospheric ozone. Biochar addition has shown potential to lower soil N2O emission, with the mechanisms remaining unclear. We incubated eucalypt biochar (550 °C)--0, 1 and 5% (w/w) in Ferralsol at 3 water regimes (12, 39 and 54% WFPS)--in a soil column, f...

We develop an inventory of global N2O emissions from natural ecosystem soils using an artificial neural network approach and field observational data of N2O fluxes. We estimate that the global soil N2O source strength from natural ecosystems is 3.37 Tg (1 Tg 1⁄4 1012 g) N per year with an uncertainty ranging from 1.96 to 4.56 Tg N per year in 2000. While our global estimate is lower than other ...

Soil fumigation has recently been shown to affect the greenhouse gas balance by increasing emissions of nitrous oxide (N2O) following chloropicrin (CP) application. However, the exactmechanisms of this increasewere not investigated. The purpose of this study was to elucidate potential mechanisms of CP-induced N2O production through laboratory incubations using chemical inhibitors (acetylene, an...

The isotopic signatures of 15N and 18O in N2O emitted from tropical soils vary both spatially and temporally, leading to large uncertainty in the overall tropical source signature and thereby limiting the utility of isotopes in constraining the global N2O budget. Determining the reasons for spatial and temporal variations in isotope signatures requires that we know the isotope enrichment factor...

Nonpoint source contamination of surface and groundwater resources with nitrate-N (NO3-N) has been linked to agriculture across the midwestern USA. A 4-yr study was conducted to assess the extent of NO3-N leaching in a central Iowa field. Water flow rate was monitored continuously and data were stored on an internal datalogger. Water samples for chemical analysis were collected weekly provided ...

The isotopic signatures of N and O in N2O emitted from tropical soils vary both spatially and temporally, leading to large uncertainty in the overall tropical source signature and thereby limiting the utility of isotopes in constraining the global N2O budget. Determining the reasons for spatial and temporal variations in isotope signatures requires that we know the isotope enrichment factors fo...

Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N2O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N2O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared. N2O emission data showed large temporal and spatial variati...

The oxidation of ammonium is a key step in the nitrogen cycle, regulating the production of nitrate, nitrous oxide and dinitrogen. In marine and freshwater ecosystems, anaerobic ammonium oxidation coupled to nitrite reduction, termed anammox, accounts for up to 67% of dinitrogen production1–3. Dinitrogen production through anaerobic ammonium oxidation has not been observed in terrestrial ecosys...

Potato is considered a nitrogen (N) intensive plant with low N use efficiency (NUE). The current study introduced an excellent approach by combining dicyandiamide (DCD), moringa seed oil (MSO), or zeolite (ZE), fertilizer for maximizing potato tuber yields and NUE as well minimizing tubers nitrate (NO3?) accumulation. impact of these materials on soil availability gaseous emissions (NH3, N2O) w...