 |
| Titel |
Temporal variability in bioassays of the stomatal ammonia compensation point in relation to plant and soil nitrogen parameters in intensively managed grassland |
| VerfasserIn |
M. Mattsson, B. Herrmann, M. David, B. Loubet, M. Riedo, M. R. Theobald, M. A. Sutton, D. Bruhn, A. Neftel, J. K. Schjoerring |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 2 ; Nr. 6, no. 2 (2009-02-11), S.171-179 |
| Datensatznummer |
250003428
|
| Publikation (Nr.) |
 copernicus.org/bg-6-171-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| The exchange of ammonia between crop canopies and the atmosphere depends on
a range of plant parameters and climatic conditions. However, little is
known about effects of management factors. We have here investigated the
stomatal ammonia compensation point in response to cutting and fertilization
of a grass sward dominated by Lolium perenne. Tall grass had a very low NH3
compensation point (around 1 nmol mol−1), reflecting the fact that leaf
nitrogen (N) concentration was very low. During
re-growth after cutting, leaf tissue concentrations of NO3−,
NH4+, soluble N and total N increased along with apoplastic
NH4+ concentrations. In contrast, apoplastic pH decreased resulting
in largely unaltered NH3 compensation points. Nitrogen fertilization
one week after cutting caused the apoplastic NH4+ concentration of
the newly emerging leaves to increase dramatically. The NH3
compensation point peaked between 15 and 25 nmol mol−1 the day after
the fertiliser was applied and thereafter decreased over the following 10
days until reaching the same level as before fertilisation. Ammonium
concentrations in leaf apoplast, bulk tissue and litter were positively
correlated (P=0.001) throughout the experimental period. Bulk tissue
NH4+ concentrations, total plant N and soil NH4+
concentrations also showed a positive correlation. A very high potential
for NH3 emission was shown by the plant litter. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|