The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland
Intensively managed grazed grasslands in temperate climates are globally important environments for the exchange of the greenhouse gases (GHGs) carbon dioxide (CO<sub>2</sub>), nitrous oxide (N<sub>2</sub>O) and methane (CH<sub>4</sub>). We assessed the N and C bu...
| Main Authors: | , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2017-04-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/14/2069/2017/bg-14-2069-2017.pdf |
| _version_ | 1811302042812022784 |
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| author | S. K. Jones C. Helfter M. Anderson M. Coyle C. Campbell D. Famulari C. Di Marco N. van Dijk Y. S. Tang C. F. E. Topp R. Kiese R. Kindler J. Siemens M. Schrumpf K. Kaiser E. Nemitz P. E. Levy R. M. Rees M. A. Sutton U. M. Skiba |
| author_facet | S. K. Jones C. Helfter M. Anderson M. Coyle C. Campbell D. Famulari C. Di Marco N. van Dijk Y. S. Tang C. F. E. Topp R. Kiese R. Kindler J. Siemens M. Schrumpf K. Kaiser E. Nemitz P. E. Levy R. M. Rees M. A. Sutton U. M. Skiba |
| author_sort | S. K. Jones |
| collection | DOAJ |
| description | Intensively managed grazed grasslands in temperate climates are
globally important environments for the exchange of the greenhouse gases
(GHGs) carbon dioxide (CO<sub>2</sub>), nitrous oxide (N<sub>2</sub>O) and methane
(CH<sub>4</sub>). We assessed the N and C budget of a mostly grazed and occasionally
cut and fertilised grassland in SE Scotland by measuring or modelling all
relevant imports and exports to the field as well as changes in soil C and N
stocks over time. The N budget was dominated by import from inorganic and
organic fertilisers (21.9 g N m<sup>−2</sup> a<sup>−1</sup>) and losses from leaching
(5.3 g N m<sup>−2</sup> a<sup>−1</sup>), N<sub>2</sub> emissions
(2.9 g N m<sup>−2</sup> a<sup>−1</sup>),
and NO<sub><i>x</i></sub> and NH<sub>3</sub> volatilisation (3.9 g N m<sup>−2</sup> a<sup>−1</sup>), while
N<sub>2</sub>O emission was only 0.6 g N m<sup>−2</sup> a<sup>−1</sup>. The efficiency of N
use by animal products (meat and wool) averaged 9.9 % of total N input
over only-grazed years (2004–2010). On average over 9 years (2002–2010), the balance of N fluxes suggested that 6.0 ± 5.9 g N m<sup>−2</sup> a<sup>−1</sup> (mean ± confidence interval at
<i>p</i> > 0.95) were stored in the soil. The largest component of the C budget was the
net ecosystem exchange of CO<sub>2</sub> (NEE), at an average uptake rate of 218 ± 155 g C m<sup>−2</sup> a<sup>−1</sup> over the 9 years. This sink strength
was offset by carbon export from the field mainly as grass offtake for
silage (48.9 g C m<sup>−2</sup> a<sup>−1</sup>) and leaching (16.4 g C m<sup>−2</sup> a<sup>−1</sup>). The other export terms, CH<sub>4</sub> emissions from the soil, manure applications and enteric fermentation, were negligible and only
contributed to 0.02–4.2 % of the total C losses. Only a small fraction of
C was incorporated into the body of the grazing animals. Inclusion of these
C losses in the budget resulted in a C sink strength of 163 ± 140 g C m<sup>−2</sup> a<sup>−1</sup>. By contrast, soil stock measurements taken in May
2004 and May 2011 indicated that the grassland sequestered N in the 0–60 cm
soil layer at 4.51 ± 2.64 g N m<sup>−2</sup> a<sup>−1</sup> and lost C at a
rate of 29.08 ± 38.19 g C m<sup>−2</sup> a<sup>−1</sup>. Potential
reasons for the discrepancy between these estimates are probably an
underestimation of C losses, especially from leaching fluxes as well as from
animal respiration. The average greenhouse gas (GHG) balance of the
grassland was −366 ± 601 g CO<sub>2</sub> eq. m<sup>−2</sup> yr<sup>−1</sup> and was strongly
affected by CH<sub>4</sub> and N<sub>2</sub>O emissions. The GHG sink strength of the
NEE was reduced by 54 % by CH<sub>4</sub> and N<sub>2</sub>O emissions. Estimated
enteric fermentation from ruminating sheep proved to be an important
CH<sub>4</sub> source, exceeding the contribution of N<sub>2</sub>O to the GHG budget in
some years. |
| first_indexed | 2024-04-13T07:20:52Z |
| format | Article |
| id | doaj.art-0ae63168e7ab4484b9cab7ce888c7829 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-13T07:20:52Z |
| publishDate | 2017-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-0ae63168e7ab4484b9cab7ce888c78292022-12-22T02:56:37ZengCopernicus PublicationsBiogeosciences1726-41701726-41892017-04-011482069208810.5194/bg-14-2069-2017The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grasslandS. K. Jones0C. Helfter1M. Anderson2M. Coyle3C. Campbell4D. Famulari5C. Di Marco6N. van Dijk7Y. S. Tang8C. F. E. Topp9R. Kiese10R. Kindler11J. Siemens12M. Schrumpf13K. Kaiser14E. Nemitz15P. E. Levy16R. M. Rees17M. A. Sutton18U. M. Skiba19Centre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKScotland's Rural College, King's Buildings, West Mains Road, Edinburgh, EH9 3JG, UKKarlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Kreuzeckbahnstr. 19, 82467 Garmisch-Partenkirchen, GermanyDepartment of Waste Management and Environmental Research, Technische Universität Berlin, Franklinstr. 29, 10587 Berlin, GermanyChair of Soil Resources, Institute of Soil Science and Soil Conservation, iFZ Research Centre for BioSystems, Land Use and Nutrition, Justus Liebig University Giessen, Heinrich-Buff-Ring 26–32, 35392 Giessen, GermanyDepartment for Biogeochemical Processes, Max Plank Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745 Jena, GermanySoil Science and Soil Protection, Martin Luther University Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle (Saale), GermanyCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKScotland's Rural College, King's Buildings, West Mains Road, Edinburgh, EH9 3JG, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKCentre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 QB, UKIntensively managed grazed grasslands in temperate climates are globally important environments for the exchange of the greenhouse gases (GHGs) carbon dioxide (CO<sub>2</sub>), nitrous oxide (N<sub>2</sub>O) and methane (CH<sub>4</sub>). We assessed the N and C budget of a mostly grazed and occasionally cut and fertilised grassland in SE Scotland by measuring or modelling all relevant imports and exports to the field as well as changes in soil C and N stocks over time. The N budget was dominated by import from inorganic and organic fertilisers (21.9 g N m<sup>−2</sup> a<sup>−1</sup>) and losses from leaching (5.3 g N m<sup>−2</sup> a<sup>−1</sup>), N<sub>2</sub> emissions (2.9 g N m<sup>−2</sup> a<sup>−1</sup>), and NO<sub><i>x</i></sub> and NH<sub>3</sub> volatilisation (3.9 g N m<sup>−2</sup> a<sup>−1</sup>), while N<sub>2</sub>O emission was only 0.6 g N m<sup>−2</sup> a<sup>−1</sup>. The efficiency of N use by animal products (meat and wool) averaged 9.9 % of total N input over only-grazed years (2004–2010). On average over 9 years (2002–2010), the balance of N fluxes suggested that 6.0 ± 5.9 g N m<sup>−2</sup> a<sup>−1</sup> (mean ± confidence interval at <i>p</i> > 0.95) were stored in the soil. The largest component of the C budget was the net ecosystem exchange of CO<sub>2</sub> (NEE), at an average uptake rate of 218 ± 155 g C m<sup>−2</sup> a<sup>−1</sup> over the 9 years. This sink strength was offset by carbon export from the field mainly as grass offtake for silage (48.9 g C m<sup>−2</sup> a<sup>−1</sup>) and leaching (16.4 g C m<sup>−2</sup> a<sup>−1</sup>). The other export terms, CH<sub>4</sub> emissions from the soil, manure applications and enteric fermentation, were negligible and only contributed to 0.02–4.2 % of the total C losses. Only a small fraction of C was incorporated into the body of the grazing animals. Inclusion of these C losses in the budget resulted in a C sink strength of 163 ± 140 g C m<sup>−2</sup> a<sup>−1</sup>. By contrast, soil stock measurements taken in May 2004 and May 2011 indicated that the grassland sequestered N in the 0–60 cm soil layer at 4.51 ± 2.64 g N m<sup>−2</sup> a<sup>−1</sup> and lost C at a rate of 29.08 ± 38.19 g C m<sup>−2</sup> a<sup>−1</sup>. Potential reasons for the discrepancy between these estimates are probably an underestimation of C losses, especially from leaching fluxes as well as from animal respiration. The average greenhouse gas (GHG) balance of the grassland was −366 ± 601 g CO<sub>2</sub> eq. m<sup>−2</sup> yr<sup>−1</sup> and was strongly affected by CH<sub>4</sub> and N<sub>2</sub>O emissions. The GHG sink strength of the NEE was reduced by 54 % by CH<sub>4</sub> and N<sub>2</sub>O emissions. Estimated enteric fermentation from ruminating sheep proved to be an important CH<sub>4</sub> source, exceeding the contribution of N<sub>2</sub>O to the GHG budget in some years.http://www.biogeosciences.net/14/2069/2017/bg-14-2069-2017.pdf |
| spellingShingle | S. K. Jones C. Helfter M. Anderson M. Coyle C. Campbell D. Famulari C. Di Marco N. van Dijk Y. S. Tang C. F. E. Topp R. Kiese R. Kindler J. Siemens M. Schrumpf K. Kaiser E. Nemitz P. E. Levy R. M. Rees M. A. Sutton U. M. Skiba The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland Biogeosciences |
| title | The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland |
| title_full | The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland |
| title_fullStr | The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland |
| title_full_unstemmed | The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland |
| title_short | The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland |
| title_sort | nitrogen carbon and greenhouse gas budget of a grazed cut and fertilised temperate grassland |
| url | http://www.biogeosciences.net/14/2069/2017/bg-14-2069-2017.pdf |
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