Nitrous oxide emission factors for agricultural soils in Great Britain: the impact of soil water‐filled pore space and other controlling variables

Measurements were made of nitrous oxide (N2O) emissions from N-fertilised ungrazed grassland and arable land at sites widely distributed across Great Britain during 1999–2001. The closed static chamber method was used throughout. Emissions varied widely throughout the year at each site, and between sites. Daily fluxes up to 1200 g N2O–N ha−1 d−1 were recorded. The highest annual flux was 27.6 kg N2O–N ha−1 at a grassland site in Wales, whereas the lowest, 1.7 kg N2O–N ha−1, occurred on a soil overlying chalk in southern England. The key factors affecting N2O emissions from agricultural soil were soil WFPS, temperature and soil NO3––N content. On grassland, rainfall (particularly around the time of N application), with its consequent effect on water-filled pore space (WFPS), was the main driving factor during the growing season. Annual emission factors (EFs), uncorrected for background emission, varied from 0.4 to 6.5% of the nitrogen (N) applied, covering a similar range for grassland to that found previously for sites restricted to Scotland. Continued monitoring at a grassland reference site near Edinburgh showed that annual EFs vary greatly from year to year, even with similar management, and that several years' data are required to produce a robust mean EF. The overall distribution of EFs in this and previous studies was log-normal. The EFs for small-grain cereals (and oilseed rape) peaked at a much lower value than those for grassland, whereas the values for leafy vegetables and potato crops fitted well into the grassland distribution. These differences in EF between various types of crop should be taken into account when compiling regional or national N2O emission inventories.

[1]  C. Klein,et al.  Denitrification in grassland soils in the Netherlands in relation to irrigation, N-application rate, soil water content and soil temperature , 1996 .

[2]  Changsheng Li,et al.  A model of nitrous oxide evolution from soil driven by rainfall events: 1. Model structure and sensitivity , 1992 .

[3]  K. Dobbie,et al.  The effects of temperature, water‐filled pore space and land use on N2O emissions from an imperfectly drained gleysol , 2001 .

[4]  J. Munch,et al.  Effect of crop-specific field management and N fertilization on N2O emissions from a fine-loamy soil , 2001, Nutrient Cycling in Agroecosystems.

[5]  G. Velthof,et al.  Effects of type and amount of applied nitrogen fertilizer on nitrous oxide fluxes from intensively managed grassland , 1996, Nutrient Cycling in Agroecosystems.

[6]  G. Velthof,et al.  Seasonal variations in nitrous oxide losses from managed grasslands in The Netherlands , 1996, Plant and Soil.

[7]  Keith A. Smith,et al.  Effects of temperature, water content and nitrogen fertilisation on emissions of nitrous oxide by soils , 1998 .

[8]  Keith A. Smith,et al.  Nitrous oxide emissions from intensive agricultural systems: Variations between crops and seasons, key driving variables, and mean emission factors , 1999 .

[9]  K. A. Smith,et al.  Nitrous oxide emissions from fertilised grassland: A 2-year study of the effects of N fertiliser form and environmental conditions , 1997, Biology and Fertility of Soils.

[10]  B. Ball,et al.  Long term monitoring of soil gas fluxes with closed chambers using automated and manual systems , 1999 .

[11]  D. Serça,et al.  N2O and CH4 emissions from fertilized agricultural soils in southwest France , 2004, Nutrient Cycling in Agroecosystems.

[12]  S. Frolking,et al.  N2O emissions from humid tropical agricultural soils: effects of soil moisture, texture and nitrogen availability , 2001 .

[13]  D. R. Hastie,et al.  The production of atmospheric NOx and N2O from a fertilized agricultural soil , 1991 .

[14]  G. Velthof,et al.  Nitrous oxide fluxes from grassland in the Netherlands: II. Effects of soil type, nitrogen fertilizer application and grazing , 1995 .

[15]  Friedrich Beese,et al.  Seasonal variation of N2O and CH4 fluxes in differently managed arable soils in southern Germany , 1995 .

[16]  Keith A. Smith,et al.  The impact of sampling frequency and sampling times on chamber‐based measurements of N2O emissions from fertilized soils , 2001 .

[17]  A. Bouwman.  Direct emission of nitrous oxide from agricultural soils , 1996, Nutrient Cycling in Agroecosystems.

[18]  D. Powlson,et al.  Denitrification losses of nitrogen fertilizer applied to winter wheat following ley and arable rotations as estimated by acetylene inhibition and 15N balance , 1993 .

[19]  Ewald Schnug,et al.  Nitrous oxide release from arable soil: Importance of N-fertilization, crops and temporal variation , 1998 .

[20]  Keith A. Smith,et al.  Automated gas chromatographic analysis system for micrometeorological measurements of trace gas fluxes , 1994 .

[21]  C. Kroeze,et al.  Closing the global N2O budget: A retrospective analysis 1500–1994 , 1999 .

[22]  C. Kessel,et al.  Ambient nitrous oxide emissions from different landform complexes as affected by simulated rain‐fall 1 , 1995 .

[23]  J. Rydén.  Denitrification loss from a grassland soil in the field receiving different rates of nitrogen as ammonium nitrate , 1983 .

[24]  J. C. Ryden,et al.  Nitrous oxide evolution from irrigated land. , 1980 .

[25]  K. A. Smith,et al.  Predicting N2O emissions from agricultural land through related soil parameters , 2000 .

[26]  C. Nevison,et al.  Closing the global N2O budget: nitrous oxide emissions through the agricultural nitrogen cycle , 1998, Nutrient Cycling in Agroecosystems.

[27]  Keith A. Smith,et al.  Emissions of N2O from Scottish agricultural soils, as a function of fertilizer N , 1998, Nutrient Cycling in Agroecosystems.

[28]  K. A. Smith,et al.  Nitrous oxide emissions from grassland and spring barley, following N fertiliser application with and without nitrification inhibitors , 1997, Biology and Fertility of Soils.

[29]  Keith A. Smith.  The potential for feedback effects induced by global warming on emissions of nitrous oxide by soils , 1997 .

[30]  D. Keeney,et al.  Effect of Temperature on the Gaseous Nitrogen Products of Denitrification in a Silt Loam Soil1 , 1979 .