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	<journal>
		<journal_title>Biogeosciences</journal_title>
		<journal_url>www.biogeosciences.net</journal_url>
		<issn>1726-4170</issn>
		<eissn>1726-4189</eissn>
		<volume_number>6</volume_number>
		<issue_number>1</issue_number>
		<publication_year>2009</publication_year>
	</journal>
	<doi>10.5194/bg-6-15-2009</doi>
	<article_url>http://www.biogeosciences.net/6/15/2009/</article_url>
	<abstract_html>http://www.biogeosciences.net/6/15/2009/bg-6-15-2009.html</abstract_html>
	<fulltext_pdf>http://www.biogeosciences.net/6/15/2009/bg-6-15-2009.pdf</fulltext_pdf>
	<start_page>15</start_page>
	<end_page>23</end_page>
	<publication_date>2009-01-06</publication_date>
	<article_title content_type="html">Vertical structure and diurnal variability of ammonia exchange potential within an intensively managed grass canopy</article_title>
	<authors>
		<author numeration="1" affiliations="1">
			<name>B. Herrmann</name>
		</author>
		<author numeration="2" affiliations="2,7">
			<name>M. Mattsson</name>
		</author>
		<author numeration="3" affiliations="3">
			<name>S. K. Jones</name>
		</author>
		<author numeration="4" affiliations="4">
			<name>P. Cellier</name>
		</author>
		<author numeration="5" affiliations="5">
			<name>C. Milford</name>
		</author>
		<author numeration="6" affiliations="6">
			<name>M. A. Sutton</name>
		</author>
		<author numeration="7" affiliations="2">
			<name>J. K. Schjoerring</name>
		</author>
		<author numeration="8" affiliations="1">
			<name>A. Neftel</name>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">Agroscope Reckenholz-Tänikon Research Station ART, Reckenholzstrasse 191, 8046 Zürich, Switzerland</affiliation>
		<affiliation numeration="2" content_type="html">Plant and Soil Science Laboratory, University of Copenhagen, Faculty of Life Sciences, Thorvaldsensvej 40, 1871 Frederiksberg C, Copenhagen, Denmark</affiliation>
		<affiliation numeration="3" content_type="html">Scottish Agricultural College, King&apos;s Buildings, West Mains Road, Edinburgh EH9 3JG, UK</affiliation>
		<affiliation numeration="4" content_type="html">Inst. National de la Recherche Agronomique (INRA), UMR Environnement et Grandes Cultures, Thiverval-Grignon, France</affiliation>
		<affiliation numeration="5" content_type="html">Institute of Earth Sciences &quot;Jaume Almera&quot;, CSIC, Lluis Solé I Sabaris, 08028, Barcelona, Spain</affiliation>
		<affiliation numeration="6" content_type="html">Natural Environmental Research Council, Centre for Ecology and Hydrology, Edinburgh Research Station, Penicuik EH26 0QB, Midlothian, UK</affiliation>
		<affiliation numeration="7" content_type="html">now at: Section for Economy and Technology, Halmstad University, Halmstad, 30118, Sweden</affiliation>
	</affiliations>
	<abstract content_type="html">Stomatal ammonia compensation points (&amp;chi;&lt;sub&gt;s&lt;/sub&gt;) of grass species on a mixed
fertilized grassland were determined by measurements of apoplastic
[NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] and [H&gt;&lt;sup&gt;+&lt;/sup&gt;] in the field. Calculated &amp;chi;&lt;sub&gt;s&lt;/sub&gt;  values were
compared with in-canopy atmospheric NH&lt;sub&gt;3&lt;/sub&gt; concentration (&amp;chi;&lt;sub&gt;a&lt;/sub&gt;)
measurements.
&lt;br&gt;&lt;br&gt;
Leaf apoplastic [NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] increased by a factor of two from the
lowest level in the canopy to the top level. Bulk leaf [NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] and
especially [NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;&amp;minus;&lt;/sup&gt;] slightly increased at the bottom of the canopy
and these concentrations were very high in senescent plant litter.
Calculated &amp;chi;&lt;sub&gt;s&lt;/sub&gt; values were below atmospheric &amp;chi;&lt;sub&gt;s&lt;/sub&gt; at
all canopy levels measured, indicating that the grassland was characterized
by NH&lt;sub&gt;3&lt;/sub&gt; deposition before cutting. This was confirmed by the &amp;chi;&lt;sub&gt;a&lt;/sub&gt;
profile, showing the lowest &amp;chi;&lt;sub&gt;a&lt;/sub&gt; close to the ground (15 cm above soil
surface) and an increase in &amp;chi;&lt;sub&gt;a&lt;/sub&gt; with canopy height. Neither &amp;chi;&lt;sub&gt;s&lt;/sub&gt;
nor &amp;chi;&lt;sub&gt;a&lt;/sub&gt; could be measured close to the soil surface, however, the
[NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] in the litter material indicated a high potential for
NH&lt;sub&gt;3&lt;/sub&gt; emission.
&lt;br&gt;&lt;br&gt;
A diurnal course in apoplastic [NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] was seen in the regrowing
grass growing after cutting, with highest concentration around noon. Both
apoplastic and tissue [NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] increased in young grass compared to
tall grass. Following cutting, in-canopy gradients of atmospheric &amp;chi;&lt;sub&gt;a&lt;/sub&gt;
showed NH&lt;sub&gt;3&lt;/sub&gt; emission but since calculated &amp;chi;&lt;sub&gt;s&lt;/sub&gt; values of the cut
grass were still lower than atmospheric NH&lt;sub&gt;3&lt;/sub&gt; concentrations, the
emissions could not entirely be explained by stomatal NH&lt;sub&gt;3&lt;/sub&gt; loss. High
tissue [NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] in the senescent plant material indicated that this
fraction constituted an NH&lt;sub&gt;3&lt;/sub&gt; source. After fertilization,
[NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] increased both in apoplast and leaf tissue with the most
pronounced increase in the former compared to the latter. The diurnal
pattern in apoplastic [NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] was even more pronounced after
fertilization and calculated &amp;chi;&lt;sub&gt;s&lt;/sub&gt; values were generally higher, but
remained below atmospheric [NH&lt;sub&gt;3&lt;/sub&gt;].</abstract>
	<references>
		<reference numeration="1" content_type="text"> % vor jede Referenz Burkhardt, J., Flechard, C. R., Gresens, F., Mattsson, M. E., Jongejan, P. A. C., Erisman, J. W., Weidinger, T., Meszaros, R., Nemitz, E., and Sutton, M. A.: Modeling the dynamic chemical interactions of atmospheric ammonia and other trace gases with measured leaf surface wetness in a managed grassland canopy, Biogeosciences Discuss., 5, 2505–2539, 2008. </reference>
		<reference numeration="2" content_type="text"> Bussink, D. W., Lowry, A., Harper, A., and Corré, W. J.: Ammonia transport in a temperate grassland: ll. Diurnal fluctuations in response to weather and management conditions, Agron. J., 88, 621–626, 1996. </reference>
		<reference numeration="3" content_type="text"> David, M., Roche, R., Mattsson, M., Sutton, M. A., Schjoerring, J. K., Daemmgen, U., and Cellier, P.: Analysis of ammonia fluxes with intensively managed grassland using dynamic chambers ll. The effect of management options, Biogeosciences Discuss., in press, 2008. </reference>
		<reference numeration="4" content_type="text"> Denmead, O. T., Freney, J. R., and Simpson, J. R.: A closed ammnonia cycle within a plant canopy, Soil Biol. Biochem., 8, 161–164, 1976. </reference>
		<reference numeration="5" content_type="text"> Farquhar, G. D., Firth, P. M., Wetselaar, R., and Weir, B: On the gaseous exchange of ammonia between leaves and the environment: determination of the ammonia compensation point, Plant Physiol., 66, 710–714, 1980. </reference>
		<reference numeration="6" content_type="text"> Flechard, C. R., Fowler, D., Sutton, M. A., and Cape, J. N.: A dynamic chemical model of bi-directional ammonia exchange between semi-natural vegetation and the atmosphere, Q. J. Roy. Meteor. Soc., 125, 2611–2641, 1999. </reference>
		<reference numeration="7" content_type="text"> Genfa, Z. and Dasgupta, P. K.: Fluorometric measurement of aqueous ammonium ion in a flow injection system, Anal. Chem., 61, 408–412, 1989. </reference>
		<reference numeration="8" content_type="text"> Harper, L. A., Bussink ,D. W., van der Meer, H. G., and Corré, W. J.: Ammonia transport in a temperate grassland: 1. Seasonal transport in relation to soil fertility and crop management, Agron. J., 88, 614–621, 1996. </reference>
		<reference numeration="9" content_type="text"> Herrmann, B., Jones, S. K., Fuhrer, J., Feller, U., and Neftel, A.: N budget and NH&lt;sub&gt;3&lt;/sub&gt; exchange of a grass/clover crop at two levels of N application, Plant and Soil, 235, 243–252, 2001. </reference>
		<reference numeration="10" content_type="text"> Hill, P., Raven, J. A., Loubet, B., Fowler, D., and Sutton, M. A.: Comparison of gas exchange and bioassay determinations of the ammonia compensation point in \textitLuzula \textitsylvatica, (Huds.) Gaud. Plant Physiol., 125, 476–487, 2001. </reference>
		<reference numeration="11" content_type="text"> Hill, P. W., Raven, J. A., and Sutton, M. A.: Leaf age-related differences in apoplastic NH$_4^+$ concentration, pH and the NH&lt;sub&gt;3&lt;/sub&gt; compensation point for a wild perennial, J. Exp. Bot., 53, 277–286, 2002. </reference>
		<reference numeration="12" content_type="text"> Horvath, L., Astalos, M., Fuhrer, E., Meszaros, R., and Weidinger, T.: Measurement of ammonia exchange over grassland in the Hungarian Great Plain, Agric. Forest Meteorol., 130, 282–298, 2005. </reference>
		<reference numeration="13" content_type="text"> Husted, S. and Schjoerring, J. K.: Apoplastic pH and ammonium concentration in leaves of \textitBrassica napus L., Plant Physiology, 190, 1453–1460, 1995. </reference>
		<reference numeration="14" content_type="text"> Husted, S., Mattsson, M., and Schjoerring, J. K.: Ammonia compensation points in two cultivars of \textitHordeum vulgare L., during vegetative and generative growth, Plant, Cell Environ., 19, 1299–1306, 1996. </reference>
		<reference numeration="15" content_type="text"> Husted, S. and Schjoerring, J. K.: Ammonia flux between oilseed rape plants and the atmosphere in response to changes in leaf temperature, light intensity and air humidity, Plant Physiol., 112, 67–74, 1996. </reference>
		<reference numeration="16" content_type="text"> Husted, S., Schjoerring, J. K., Nielsen, K. H., Nemitz, E., and Sutton, M. A.: Stomatal compensation points for ammonia in oilseed rape plants under field conditions, Agric. Forest Meteorol., 105, 371–383, 2000. </reference>
		<reference numeration="17" content_type="text"> Husted, S., Mattsson, M., Möllers, C., Wallbraun, M., and Schjoerring, J. K.: Photorespiratory NH$_4^+$ production in leaves of wildtype and GS2-antisense oilseed rape, Plant Physiol., 130, 989–998, 2002. </reference>
		<reference numeration="18" content_type="text"> Kruit, R., Erismann, J. W., van Pul, W. A. J., Otjes, R. P., Hofschreuder, P., Jacobs, A. F. G., and Holtslag, A. M.: Ammonia fluxes and derived canopy compensation points over non-fertilized agricultural grassland in The Netherlands using the new gradient ammonia-high accuracy-monitor (GRAHAM), Atmos. Environ., 41, 1275–1287, 2007. </reference>
		<reference numeration="19" content_type="text"> Lemon, E. and van Houtte, R.: Ammonia exchange at the land surface, Agron. J., 72, 876–883, 1980. </reference>
		<reference numeration="20" content_type="text"> Loubet, B., Milford, C., Hill, P. W., Tang, Y. S., Cellier, P, and Sutton, M. A.: Seasonal variability of apoplastic NH$_4^+$ and pH in an intensively managed grassland, Plant Soil, 238, 97–110, 2002. </reference>
		<reference numeration="21" content_type="text"> Mattsson, M., Häusler, R. E., Leegood, R. C., Lea, P. J., and Schjoerring, J. K.: Leaf-atmosphere NH&lt;sub&gt;3&lt;/sub&gt; exchange in barley mutants with reduced activities of glutamine synthetase, Plant Physiol., 114, 1307–1312, 1997. </reference>
		<reference numeration="22" content_type="text"> Mattsson, M., Husted, S., and Schjoerring, J. K.: Influence of nitrogen nutrition and metabolism on ammonia volatilization in plants, Nutr. Cycl. Agroecosys., 51, 35–40, 1998. </reference>
		<reference numeration="23" content_type="text"> Mattsson, M. and Schjoerring, J. K.: Dynamic and steady state responses of inorganic nitrogen pools and NH&lt;sub&gt;3&lt;/sub&gt; exchange in leaves of \textitLolium perenne and \textitBromus erectus to changes in root supply, Plant Physiol., 128, 742–750, 2002. </reference>
		<reference numeration="24" content_type="text"> Mattsson, M. and Schjoerring, J. K.: Senescence-induced changes in apoplastic and bulk tissue ammonia concentrations of rye-grass leaves, New Phytol., 160, 489–499, 2003. </reference>
		<reference numeration="25" content_type="text"> Mattsson, M., Herrmann, B., Jones, S., Neftel, A., Sutton, M. A., and Schjoerring, J. K.: Contribution of different grass species to plant-atmosphere ammonia exchange in intensively managed grassland, Biogeosciences Discuss., 5, 2583–2605, 2008a. </reference>
		<reference numeration="26" content_type="text"> Mattsson, M., Herrmann, B., David, M., Loubet, B., Riedo, M., Theobald, M. R., Sutton, M. A., Bruhn, D., Neftel, A., and Schjoerring, J. K.: Temporal variability in bioassays of ammonia exchange potential in relation to plant and soil nitrogen parameters in intensively managed grassland, Biogeosciences Discuss., 5, 2749–2772, 2008b. </reference>
		<reference numeration="27" content_type="text"> Milford, C., Theobald, M. R., Nemitz, E., Hargreaves, K. J., Horvath, L., Raso, J., Dämmgen, U., Neftel, A., Jones, S. K., Hensen, A., Loubet, B., Cellier, P., and Sutton, M. A.: Ammonia fluxes in relation to cutting and fertilization of an intensively managed grassland derived from an inter-comparison of gradient measurements, Biogeosciences Discuss., 5, 4699–4744, 2008. </reference>
		<reference numeration="28" content_type="text"> Neftel, A., Blatter, A., Gut, A., Högger, D., Meixner, F., Ammann, C., and Nathaus, F. J.: NH&lt;sub&gt;3&lt;/sub&gt; soil and soil surface gas measurements in a triticale wheat field, Atmos. Environ., 32, 499–505, 1998. </reference>
		<reference numeration="29" content_type="text"> Nemitz, E., Sutton, M. A., Gut, A., San José, R., Husted, S., and Schjoerring, J. K.: Sources and sinks of ammonia within an oilseed rape canopy, Agric. For. Meteorol. (Ammonia Special Issue), 105(4), 385–404, 2000. </reference>
		<reference numeration="30" content_type="text"> Sharpe, R. R. and Harper, L. A.: Soil, plant and atmospheric \mboxconditions as they relate to ammonia volatilization, Fert. Res., 42, 149–158, 1995. </reference>
		<reference numeration="31" content_type="text"> Sommer, S. G., Schjoerring, J. K., and Denmead, O. T.: Ammonia emission from mineral fertilizers and fertilized crops, Adv. Agron., 82, 557–622, 2004. </reference>
		<reference numeration="32" content_type="text"> Sutton, M. A., Fowler, D., Moncrieff, J. B., and Storeton-West, R. L.: The exchange of atmospheric ammonia with vegetated surfaces, II. Fertilized vegetation, Q. J. Roy. Meteor. Soc., 119, 1047–1070, 1993. </reference>
		<reference numeration="33" content_type="text"> Sutton, M., Schjoerring, J. K., and Wyers, P.:: Plant-atmosphere exchange of ammonia, Phil. Trans. R. Soc. London, 351, 261–278, 1995. </reference>
		<reference numeration="34" content_type="text"> Sutton, M. A., Nemitz, E. , Erisman ,J. W., Beier, C., Bahl, K. B., Cellie, P., de Vries, W., Cotrufo, F., Skiba, U., Di Marco, C., Jones, S., Laville, P., Soussana, J. F., Loubet, B., Twigg, M., Famulari, D., Whitehead, J., Gallagher, M. W., Neftel, A., Flechard, C. R., Herrmann, B., Calanca, P. L., Schjoerring, J. K., Daemmgen, U., Horvath, L., Tang, Y. S., Emmett, B. A., Tietema, A., Penuelas, J., Kesik, M., Brueggemann, N., Pilegaard, K., Vesala, T., Campbell, C. L., Olesen, J. E., Dragosits, U., Theobald, M. R., Levy, P., Mobbs, D. C., Milne, R., Viovy, N., Vuichard, N., Smith, J. U., Smith, P., Bergamaschi, P., Fowler, D., and Reis, S.: Challenges in quantifying biosphere-atmosphere exchange of nitrogen species, Environ. Pollut., 150, 125–139, 2007. </reference>
		<reference numeration="35" content_type="text"> Sutton, M. A., Nemitz, E., Theobald, M. R., Milford, C., Dorsey, J. R., Gallagher, M. W., Hensen, A., Jongejan, P. A. C., Erisman, J. W., Mattsson, M. E., Schjoerring, J. K., Cellier, P., Loubet, B., Roche, R., Neftel, A., Hermann, B., Jones, S., Lehman, B. E., Horvath, L., Weidinger, T., Rajkai, K., Burkhardt, J., Löpmeier, F. J., and Daemmgen, U.: Dynamics of ammonia exchange with cut grassland: strategy and implementation of the GRAMINAE Integrated Experiment, Biogeosciences Discuss., 5, 3347–3407, 2008. </reference>
		<reference numeration="36" content_type="text"> Trebs, I., Lara, L. L., Zeri, L. M. M., Gatti, L. V., Artaxo, P., Dlugi, R., Slanina, J., Andreae, M. O., and Meixner, F. X.: Dry and wet deposition of inorganic nitrogen compounds to a tropical pasture site (Rondônia, Brazil), Atmos. Chem. Phys., 6, 447–469, 2006. </reference>
		<reference numeration="37" content_type="text"> van Hove, L. W. A., Heeres, P., and Bossen, M. E.: The annual variation in stomatal ammonia compensation point of rye grass (\textitLolium perenne L.) leaves in an intensively managed grassland, Atmos. Environ., 36, 2965–2977, 2002. </reference>
		<reference numeration="38" content_type="text"> Walker, J. T., Robarge, W. P., Wu, Y., and Meyers, T.: Measurement of bi-directional ammonia fluxes over soybean using the modified Bowen-ratio technique, Agr. Forest Meteorol., 138, 54–68, 2006. </reference>
	</references>
</article>
