Effects of dry and wet N deposition on vegetation and biogeochemistry of an ombrotrophic bog
van Zetten, Elleke; de Lange, Irene; Sheppard, Lucy J.; Leith, Ian D.; Crossley, Alan; van den Berg, Leon; Roelofs, Jan. 2006 Effects of dry and wet N deposition on vegetation and biogeochemistry of an ombrotrophic bog. In: Caper 2006. Centre for Ecology and Hydrology, 9, 1pp.Before downloading, please read NORA policies.
It has repeatedly been shown that increased nitrogen (N) deposition results in dramatic shifts in vegetation composition. The sources of N-deposition vary from agriculture (mainly NH3 and NH4) to industry and traffic (mainly NOx). Effects of these different N forms on the vegetation and biogeochemistry of an ombrotrophic peat bog, Whim Moss (~15km southwest of Edinburgh), have been investigated since April 2002, by employing an automate N manipulation system. This field experiment, uniquely, offers the possibility to investigate the effects of the different N forms at the same site and at application rates and deposition scenarios simulating natural variation in rainfall. Within the manipulation system there are two N manipulations: Dry, where gaseous NH3 is released over a 60 m transect at concentrations that simulate a 100,000 bird poultry unit (0.4-200 μg m-3), and Wet, as soluble nitrate or ammonium, covering the full range of UK wet N-deposition (8 – 64 kg N ha-1yr-1). The effects of dry N deposition on the vegetation and biogeochemistry at different distances from the NH3 source have been analysed. In the wet N deposition experiment, 5 treatments were followed, ranging from 8-64 kg N ha-1yr-1 and differing in N form as either oxidised or reduced N. Samples of soil water were obtained using mini-rhizon samplers and were tested for pH, NH4, NO3, P and base cations. Young (1 year old) shoots of Calluna vulgaris L. (Hull), Erica tetralix L. and Sphagnum capillifolium Ehrh. (Hedw.) were harvested and tested for chlorophyll concentrations, aminoacids and P and base cation concentrations in acid digests. The preliminary results show differences between treatment N forms and N doses and along the NH3 gradient. In this presentation we will focus on the plant responses to the changes in the biochemistry. CAPER Conference
|Item Type:||Book Section|
|Programmes:||CEH Programmes pre-2009 publications > Biogeochemistry|
|NORA Subject Terms:||Atmospheric Sciences|
|Date made live:||15 Oct 2009 09:31|
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