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<front>
<journal-meta>
<journal-id journal-id-type="publisher">BG</journal-id>
<journal-title-group>
<journal-title>Biogeosciences</journal-title>
<abbrev-journal-title abbrev-type="publisher">BG</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">Biogeosciences</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1726-4189</issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/bg-10-5931-2013</article-id>
<title-group>
<article-title>Temporal and spatial variations of soil CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O fluxes at three differently managed grasslands</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Imer</surname>
<given-names>D.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Merbold</surname>
<given-names>L.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Eugster</surname>
<given-names>W.</given-names>
<ext-link>https://orcid.org/0000-0001-6067-0741</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Buchmann</surname>
<given-names>N.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Grassland Sciences Group, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland</addr-line>
</aff>
<pub-date pub-type="epub">
<day>10</day>
<month>09</month>
<year>2013</year>
</pub-date>
<volume>10</volume>
<issue>9</issue>
<fpage>5931</fpage>
<lpage>5945</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2013 D. Imer et al.</copyright-statement>
<copyright-year>2013</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/3.0/">https://creativecommons.org/licenses/by/3.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://bg.copernicus.org/articles/10/5931/2013/bg-10-5931-2013.html">This article is available from https://bg.copernicus.org/articles/10/5931/2013/bg-10-5931-2013.html</self-uri>
<self-uri xlink:href="https://bg.copernicus.org/articles/10/5931/2013/bg-10-5931-2013.pdf">The full text article is available as a PDF file from https://bg.copernicus.org/articles/10/5931/2013/bg-10-5931-2013.pdf</self-uri>
<abstract>
<p>A profound understanding of temporal and spatial variabilities of soil carbon
dioxide (CO&lt;sub&gt;2&lt;/sub&gt;), methane (CH&lt;sub&gt;4&lt;/sub&gt;) and nitrous oxide (N&lt;sub&gt;2&lt;/sub&gt;O) fluxes
between terrestrial ecosystems and the atmosphere is needed to reliably
quantify these fluxes and to develop future mitigation strategies. For
managed grassland ecosystems, temporal and spatial variabilities of these
three soil greenhouse gas (GHG) fluxes occur due to changes in environmental
drivers as well as fertilizer applications, harvests and grazing. To assess
how such changes affect soil GHG fluxes at Swiss grassland sites, we studied
three sites along an altitudinal gradient that corresponds to a management
gradient: from 400 m a.s.l. (intensively managed) to 1000 m a.s.l.
(moderately intensive managed) to 2000 m a.s.l. (extensively managed). The
alpine grassland was included to study both effects of extensive management
on CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O fluxes and the different climate regime occurring at
this altitude. Temporal and spatial variabilities of soil GHG fluxes and
environmental drivers on various timescales were determined along transects
of 16 static soil chambers at each site. All three grasslands were N&lt;sub&gt;2&lt;/sub&gt;O
sources, with mean annual soil fluxes ranging from 0.15 to
1.28 nmol m&lt;sup&gt;−2&lt;/sup&gt; s&lt;sup&gt;−1&lt;/sup&gt;. Contrastingly, all sites were weak CH&lt;sub&gt;4&lt;/sub&gt;
sinks, with soil uptake rates ranging from −0.56 to
−0.15 nmol m&lt;sup&gt;−2&lt;/sup&gt; s&lt;sup&gt;−1&lt;/sup&gt;. Mean annual soil and plant respiration
losses of CO&lt;sub&gt;2&lt;/sub&gt;, measured with opaque chambers, ranged from 5.2 to
6.5 μmol m&lt;sup&gt;−2&lt;/sup&gt; s&lt;sup&gt;−1&lt;/sup&gt;. While the environmental drivers and
their respective explanatory power for soil N&lt;sub&gt;2&lt;/sub&gt;O emissions differed
considerably among the three grasslands (adjusted &lt;i&gt;r&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt; ranging from 0.19 to
0.42), CH&lt;sub&gt;4&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt; soil fluxes were much better constrained
(adjusted &lt;i&gt;r&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt; ranging from 0.46 to 0.80) by soil water content and air
temperature, respectively. Throughout the year, spatial heterogeneity was
particularly high for soil N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; fluxes. We found permanent
hot spots for soil N&lt;sub&gt;2&lt;/sub&gt;O emissions as well as locations of permanently
lower soil CH&lt;sub&gt;4&lt;/sub&gt; uptake rates at the extensively managed alpine site.
Including hot spots was essential to obtain a representative mean soil flux
for the respective ecosystem. At the intensively managed grassland,
management effects clearly dominated over effects of environmental drivers on
soil N&lt;sub&gt;2&lt;/sub&gt;O fluxes. For CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt;, the importance of management
effects did depend on the status of the vegetation (LAI).</p>
</abstract>
<counts><page-count count="15"/></counts>
</article-meta>
</front>
<body/>
<back>
<ref-list>
<title>References</title>
<ref id="ref1">
<label>1</label><mixed-citation publication-type="other" xlink:type="simple">Ambus, P. and Christensen, S.: Measurement of N&lt;sub&gt;2&lt;/sub&gt;O emission from a fertilized grassland: A}n analysis of spatial variability, {J. Geophys. Res., 99, 16549–16555, 1994.</mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple">Baldocchi, D., Detto, M., Sonnentag, O., Verfaillie, J., Teh, Y., Silver, W., and Kelly, N.: The challenges of measuring methane fluxes and concentrations over a peatland pasture, Agr. Forest Meteorol., 153, 177–187, &lt;a href=&quot;http://dx.doi.org/10.1016/j.agrformet.2011.04.013&quot;&gt;https://doi.org/10.1016/j.agrformet.2011.04.013&lt;/a&gt;, 2012.</mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple">Ball, B., Horgan, G., Clayton, H., and Parker, J.: Spatial variability of nitrous oxide fluxes and controlling soil and topographic properties, J. Environ. Qual., 26, 1399–1409, 1997.</mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple">Beniston, M.: Mountain climates and climatic change: An overview of processes focusing on the European Alps, Pure. Appl. Geophys., 162, 1587–1606, &lt;a href=&quot;http://dx.doi.org/10.1007/s00024-005-2684-9&quot;&gt;https://doi.org/10.1007/s00024-005-2684-9&lt;/a&gt;, 2005.</mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple">Boesch, H.: Nomadismus, Transhumanz und Alpwirtschaft, Die Alpen, 27, 202–207, 1951.</mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple">Buchmann, N.: Greenhouse gas emissions from E}uropean grasslands and mitigation options, in: Grassland productivity and ecosystem services, edited by: LeMaire, G., Hodgson, J., and Chabbi, A., Grassland productivity and ecosystem services, CAB {International, UK, 92–100, 2011.</mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple">Chevan, A. and Sutherland, M.: Hierarchical partitioning, Amer. Statistician., 45, 90–96, 1991.</mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple">Christensen, S.: Nitrious oxide emission from a soil under permanent grass: S}easonal and diurnal fluctuations as influenced by manuring and fertilization, {Soil Biol. Biochem., 15, 531–536, 1983.</mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple">Ciais, P., Soussana, J., Vuichard, N., Luyssaert, S., Don, A., Janssens, I., Piao, S., Dechow, R., Lathière, J., Maignan, F., Wattenbach, M., Smith, P., Ammann, C., Freibauer, A., Schulze, E., and CARBOEUROPE Synthesis Team: The greenhouse gas balance of European grasslands, Biogeosciences Discuss., 7, 5997–6050, &lt;a href=&quot;http://dx.doi.org/10.5194/bgd-7-5997-2010&quot;&gt;https://doi.org/10.5194/bgd-7-5997-2010&lt;/a&gt;, 2010a.</mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple">Ciais, P., Wattenbach, M., Vuichard, N., Smith, P., Piao, L., Don, A., Luyssaert, S., Janssens, I., Bondeau, A., Dechow, R., Leip, A., Smith, P., Beer, C., van der Werf, G., Gervois, S., van Oost, K., Tomelleri, E., Freibauer, A., and Schulze, E.: The E}uropean carbon balance, Part 2: Croplands, {Glob. Change Biol., 16, 1409–1428, 2010b.</mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple">Dalal, R. and Allen, D.: Greenhouse gas fluxes from natural ecosystems, Aust. J. Bot., 56, 369–407, 2008.</mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple">Dietrich, C. and Osborne, M.: Estimation of covariance parameters in kriging via restricted maximum likelihood, Math. Geol., 23, 119–135, 1991.</mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple">Duan, X., Wang, X., Mu, Y., and Ouyang, Z.: Seasonal and diurnal variations in methane emissions from W}uliangsu Lake in arid regions of China, {Atmos. Environ., 39, 4479–4487, 2005.</mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple">Efron, B.: Bootstrap methods: A}nother look at the jackknife, {Ann. Stat., 7, 1–26, 1979.</mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple">Ehlers, E. and Kreutzmann, H.: High mountain pastoralism in Northern Pakistan, Franz Steiner Verlag, Stuttgart, 2000.</mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple">Finger, R., Gilgen, A., Prechsl, U., and Buchmann, N.: An economic assessment of drought effects on three grassland systems in S}witzerland, {Reg. Environ. Change, 13, 365–374, 2013.</mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple">Flechard, C., Ambus, P., Skiba, U., Rees, R., Hensen, A., van Amstel, A., van den Pol-van Dasselaar, A., Soussana, J., Jones, M., Clifton-Brown, J., Raschi, A., Horvath, L., Neftel, A., Jocher, M., Ammann, C., Leifeld, J., Fuhrer, J., Calanca, P., Thalman, E., Pilegaard, K., Marco, C. D., Campbell, C., Nemitz, E., Hargreaves, K., Levy, P., Ball, B., Jones, S., van de Bulk, W., Groot, T., Blom, M., Domingues, R., Kasper, G., Allard, V., Ceschia, E., Cellier, P., Laville, P., Henault, C., Bizouard, F., Abdalla, M., Williams, M., Baronti, S., Berretti, F., and Grosz, B.: Effects of climate and management intensity on nitrous oxide emissions in grassland systems across E}urope, {Agr. Ecosyst. Environ., 121, 135–152, 2007.</mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple">Flessa, H., Ruser, R., Schilling, R., Loftfield, N., Munch, J., Kaiser, E., and Beese, F.: N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; fluxes in potato fields: Automated measurement, management effects and temporal variation, Geoderma, 105, 307–325, 2002.</mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple">Folorunso, O. and Rolston, D.: Spatial variability of field-measured denitrification gas fluxes, Soil Sci. Soc. Am. J., 48, 1214–1219, 1984.</mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple">Glatzel, S. and Stahr, K.: Methane and nitrous oxide exchange in differently fertilised grassland in southern G}ermany, {Plant Soil, 231, 21–35, 2001.</mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple">Hartmann, A., Buchmann, N., and Niklaus, P.: A study of soil methane sink regulation in two grasslands exposed to drought and N fertilization, Plant Soil, 342, 265–275, 2011.</mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple">Hendriks, D., Dolman, A., Van der Molen, J., and van Huissteden, J.: A compact and stable eddy covariance set-up for methane measurements using off-axis integrated cavity output spectroscopy, Atmos. Chem. Phys., 8, 431–443, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-8-431-2008&quot;&gt;https://doi.org/10.5194/acp-8-431-2008&lt;/a&gt;, 2008.</mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple">IPCC, W.: The physical science basis. C}ontribution of working group I to the fourth assessment report of the {Intergovernmental Panel on Climate Change, in: Climate Change 2007, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K., Tignor, M., and Miller, H., Cambridge University Press, Cambridge, 210–215, 2007.</mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple">Janssens, I., Freibauer, A., Ciais, P., Smith, P., Nabuurs, G., Folberth, G., Schlamadinger, B., Huties, R., Ceulemans, R., Schulze, E., Valentini, R., and Dolman, A.: Europe&apos;s terrestrial biosphere absorbs 7 to 12 % of E}uropean anthropogenic {CO&lt;sub&gt;2&lt;/sub&gt; emissions, Science, 300, 1538–1542, 2003.</mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple">Jiang, C., Yu, G., Fang, H., Cao, G., and Li, Y.: Short-term effect of increasing nitrogen deposition on CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O fluxes in an alpine meadow on the Qinghai-Tibetan P}lateau, China, {Atmos. Environ., 44, 2920–2926, 2010.</mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple">Jones, S., Rees, R., Kosmas, D., Ball, B., and Skiba, U.: Carbon sequestration in a temperate grassland; management and climate controls, Soil Use Manage., 22, 132–142, 2006.</mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple">Lessard, R., Rochette, P., Gregorich, E., Desjardins, R., and Pattey, E.: CH&lt;sub&gt;4&lt;/sub&gt; fluxes from a soil amended with dairy cattle manure and ammonium nitrate, Can. J. Soil Sci., 77, 179–186, 1997.</mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple">Liebig, M., Gross, J., Kronberg, S., Phillips, R., and Hanson, J.: Grazing management contributions to net global warming potential: A long-term evaluation in the northern G}reat Plains, {J. Environ. Qual., 39, 799–809, 2010.</mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple">Maljanen, M., Martikainen, P., Aaltonen, H., and Silvola, J.: Short-term variation in fluxes of carbon dioxide, nitrous oxide and methane in cultivated and forested organic boreal soils, Soil Biol. Biochem., 34, 577–584, 2002.</mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple">Mathieu, O., Leveque, J., Heault, C., Milloux, M., Bizouard, F., and Andreux, F.: Emissions and spatial variability of N&lt;sub&gt;2&lt;/sub&gt;O, N&lt;sub&gt;2&lt;/sub&gt; and nitrous oxide mole fraction at the field scale, Soil Biol. Biochem., 38, 941–951, 2006.</mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple">Matthias, A., Blackmer, A., and Bremner, J.: A simple chamber technique for field measurement of emissions of nitrous oxide from soils, J. Environ. Qual., 9, 251–256, 1980.</mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple">Merbold, L., Ziegler, W., Mukelabai, M., and Kutsch, W.: Spatial and temporal variation of CO&lt;sub&gt;2&lt;/sub&gt; efflux along a disturbance gradient in a miombo woodland in Western Zambia, Biogeosciences, 8, 147–164, &lt;a href=&quot;http://dx.doi.org/10.5194/bg-8-147-2011&quot;&gt;https://doi.org/10.5194/bg-8-147-2011&lt;/a&gt;, 2011.</mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple">Michna, P., Eugster, W., Hiller, R., Zeeman, M., and Wanner, H.: Topoclimatological case-study of A}lpine pastures near the Albula pass in the Eastern Swiss Alps, {Geograph. Helv., in press, 2013.</mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple">Mosier, A., Schimel, D., Valentine, D., Bronson, K., and Parton, W.: Methane and nitrous oxide fluxes in native, fertilized and cultivated grasslands, Nature, 350, 330–332, 1991.</mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple">Mosier, A., Delgado, J., Cochran, V., Valentine, D., and Parton, W.: Impact of agriculture on soil consumption of atmospheric CH&lt;sub&gt;4&lt;/sub&gt; and a comparison of CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O flux in subartic, temperate and tropical grasslands, Nutr. Cycl. Agroecosys., 49, 71–83, 1997.</mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple">Myklebust, M., Hipps, L., and Ryel, R.: Comparison of eddy covariance, chamber, and gradient methods of measuring soil CO&lt;sub&gt;2&lt;/sub&gt; efflux in an annual semi-arid grass, &lt;i&gt;Bromus tectorum&lt;/i&gt;, Agr. Forest Meteorol., 148, 1894–1907, 2008.</mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple">Neftel, A., Flechard, C., Ammann, C., Conen, F., Emmenegger, L., and Zeyer, K.: Experimental assessment of N&lt;sub&gt;2&lt;/sub&gt;O background fluxes in grassland systems, Tellus B, 59, 470–482, 2007.</mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple">Peng, Q., Dong, Y., Qi, Y., Xiao, S., He, Y., and Ma, T.: Effects of nitrogen fertilization on soil respiration in temperate grassland in I}nner Mongolia, China, {Environ Earth Sci., 62, 1163–1171, 2011.</mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple">Pumpanen, J., Kolari, P., Ilvesniemi, H., Minkkinen, K., Vesala, T., Niinistö, S., Lohila, A., Larmola, T., Morero, M., Pihlatie, M., Janssens, I., Yuste, J., Gruenzweig, J., Reth, S., Subke, J., Savage, K., Kutsch, W., Ostreng, G., Ziegler, W., Anthoni, P., and Hari, P.: Comparison of different chamber techniques for measuring soil CO&lt;sub&gt;2&lt;/sub&gt; efflux, Agr. Forest Meteorol., 123, 159–176, 2004.</mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple">R Development Core Team: R: A Language and Environment for Statistical Computing, R Foundation for Statistical Computing, Vienna, Austria, &lt;a href=&quot;http://www.R-project.org&quot;&gt;http://www.R-project.org&lt;/a&gt;, ISBN 3-900051-07-0, 2010.</mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple">Rochette, R.: Towards a standard non-steady-state chamber methodology for measuring soil N&lt;sub&gt;2&lt;/sub&gt;O emissions, Anim. Feed Sci. Tech., 166–167, 141–146, 2011.</mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple">Ryden, J.: N&lt;sub&gt;2&lt;/sub&gt;O exchange between a grassland soil and the atmosphere, Nature, 292, 235–237, 1981.</mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple">Sautier, S.: Zusammensetzung und Produktiviät der Vegetation im Gebiet der ETHZ-Forschungsstation Frübül (ZG), MSc Thesis, Institute of Geography, University of Zurich, 2007.</mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple">Schaufler, G., Kitzler, B., Schindlbacher, A., Skiba, U., Sutton, M., and Zechmeister-Boltenstern, S.: Greenhouse gas emissions from E}uropean soils under different land use: effects of soil moisture and temperature, {Eur. J. Soil Sci., 61, 683–696, 2010.</mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple">Schrier-Uijl, A., Kroon, P., Hensen, A., Leffelaar, P., Berendse, F., and Veenendaal, E.: Comparison of chamber and eddy covariance-based CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; emission estimates in a heterogeneous grass ecosystem on peat, Agr. Forest Meteorol., 150, 825–831, 2010.</mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple">Schulze, E., Luyssaert, S., Ciais, P., Freibauer, A., Janssens, I., Soussana, J., Smith, P., Grace, J., Levin, I., Thiruchittampalam, B., Heimann, M., Dolman, A., Valentini, R., Bousquet, P., Peylin, P., Peters, W., Rodenbeck, C., Etiope, G., Vuichard, N., Wattenbach, M., Nabuurs, G., Poussi, Z., Nieschulze, J., and Gash, J.: Importance of methane and nitrous oxide for E}urope&apos;s terrestrial greenhouse-gas balance, {Nat. Geosci., 2, 842–850, 2009.</mixed-citation>
</ref>
<ref id="ref47">
<label>47</label><mixed-citation publication-type="other" xlink:type="simple">Sieber, R., Hollenstein, L., Odden, B., and Hurni, L.: From classic atlas design to collaborative platforms – T}he SwissAtlasPlatform Project, in: Proceedings of the 25th international conference of the ICA, Paris, {France, 2011.</mixed-citation>
</ref>
<ref id="ref48">
<label>48</label><mixed-citation publication-type="other" xlink:type="simple">Skiba, U., Hargreaves, K., Beverland, I., O&apos;Neil, D., Fowler, D., and Moncrieff, J.: Measurement of field scale N&lt;sub&gt;2&lt;/sub&gt;O emission fluxes from a wheat crop using micrometeorological techniques, Plant Soil, 181, 139–144, 1996.</mixed-citation>
</ref>
<ref id="ref49">
<label>49</label><mixed-citation publication-type="other" xlink:type="simple">Soussana, J., Allard, V., Pilegaard, K., Ambus, P., Ammann, C., Campbell, C., Ceschia, E., Clifton-Brown, J., Czobel, S., Domingues, R., Flechard, C., Fuhrer, J., Hansen, A., Horvath, L., Jones, M., Kasper, G., Martin, C., Nagy, Z., Neftel, A., Raschi, A., Baronti, S., Rees, R., Skiba, U., Stefani, P., Manca, G., Sutton, M., Tuba, Z., and Valentini, R.: Full accounting of the greenhouse gas (CO&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O, CH&lt;sub&gt;4&lt;/sub&gt; budget of nine E}uropean grassland sites, {Agr. Ecosyst. Environ., 121, 121–134, 2007.</mixed-citation>
</ref>
<ref id="ref50">
<label>50</label><mixed-citation publication-type="other" xlink:type="simple">Stiehl-Braun, P., Hartmann, A., Kandeler, E., Buchmann, N., and Niklaus, P.: Interactive effects of drought and N fertilization on the spatial distribution of methane assimilation in grassland soils, Glob. Change Biol., 17, 2629–2639, 2011.</mixed-citation>
</ref>
<ref id="ref51">
<label>51</label><mixed-citation publication-type="other" xlink:type="simple">Stone, M.: Cross-validatory choice and assessment of statistical predictions, J. R. Stat. Soc., 36, 111–147, 1974.</mixed-citation>
</ref>
<ref id="ref52">
<label>52</label><mixed-citation publication-type="other" xlink:type="simple">van den Pol-van Dasselaar, A., Corre, W., Prieme, A., Klemedtsson, A., Weslien, P., Stein, A., Klemedtsson, L., and Oenema, O.: Spatial variability of methane, nitrous oxide, and carbon dioxide emissions from drained grasslands, Soil Sci. Soc. Am. J., 62, 810–817, 1998.</mixed-citation>
</ref>
<ref id="ref53">
<label>53</label><mixed-citation publication-type="other" xlink:type="simple">Velthof, G., van Groeningen, J., Gebauer, G., Pietrzak, S., Jarvis, S., Pinto, M., Corre, W., and Oenema, O.: Temporal stability of spatial patterns of nitrous oxide fluxes from sloping grassland, J. Environ. Qual., 29, 1297–1407, 2000.</mixed-citation>
</ref>
<ref id="ref54">
<label>54</label><mixed-citation publication-type="other" xlink:type="simple">Vleeshouwers, L. and Verhagen, A.: Carbon emission and sequestration by agricultural land use: a model study for E}urope, {Glob. Change Biol., 8, 519–530, 2002.</mixed-citation>
</ref>
<ref id="ref55">
<label>55</label><mixed-citation publication-type="other" xlink:type="simple">Wagner-Riddle, C., Thurtell, G., Kidd, G., Beauchamp, E., and Sweetman, R.: Estimates of nitrous oxide emissions from agricultural fields over 28 months, Can. J. Soil Sci., 77, 135–144, 1997.</mixed-citation>
</ref>
<ref id="ref56">
<label>56</label><mixed-citation publication-type="other" xlink:type="simple">Wang, M., Guan, D., Han, S., and Wu, J.: Comparison of eddy covariance and chamber-based methods for measuring CO&lt;sub&gt;2&lt;/sub&gt; flux in a temperate mixed forest, Tree Physiol., 30, 149–163, 2009.</mixed-citation>
</ref>
<ref id="ref57">
<label>57</label><mixed-citation publication-type="other" xlink:type="simple">Wang, Y., Xue, M., Zheng, X., Ji, B., Du, R., and Wang, Y.: Effects of environmental factors on N&lt;sub&gt;2&lt;/sub&gt;O emission from and CH&lt;sub&gt;4&lt;/sub&gt; uptake by the typical grasslands in the Inner Mongolia, Chemosphere, 58, 205–215, 2005.</mixed-citation>
</ref>
<ref id="ref58">
<label>58</label><mixed-citation publication-type="other" xlink:type="simple">Weiss, R.: Das Alpwesen Graubündens: Wirtschaft, Sachkultur, Recht, Älplerarbeit und Älplerleben, Eugen Rentsch Verlag, Erlenbach–Zürich, 1941.</mixed-citation>
</ref>
<ref id="ref59">
<label>59</label><mixed-citation publication-type="other" xlink:type="simple">Willison, T., Webster, C., Goulding, K., and Powlson, D.: Methane oxidation in temperate soils – effects of land-use and the chemical form of the nitrogen fertilizer, Chemsophere, 30, 539–546, 1995.</mixed-citation>
</ref>
<ref id="ref60">
<label>60</label><mixed-citation publication-type="other" xlink:type="simple">Zeeman, M., Hiller, R., Gilgen, A., Michna, P., Pluess, P., Buchmann, N., and Eugster, W.: Management and climate impacts on the net CO&lt;sub&gt;2&lt;/sub&gt; fluxes and carbon budgets of three grasslands along an elevational gradient in S}witzerland, {Agr. Forest Meteorol., 150, 519–530, 2010.</mixed-citation>
</ref>
</ref-list>
</back>
</article>