To obtain an insight into the effects of a high ammonium deposition on trees young, coniferous trees were planted in pots in a greenhouse and treated with artificial ammonium-enriched rainwater. Application of 480 kg ammonium N ha(-1) year(-1) resulted in an increase of the shoot/root ratio. The biomass of fine roots strongly declined, as did the numbers of mycorrhizae. The fructification of the mycorrhizal fungi was totally inhibited. The nitrogen content of the needles was enhanced, but the levels of potassium, magnesium and calcium decreased sharply. The phosphorus content remained almost unaffected. Much of the nitrogen was stored as arginine. The levels of leaf pigments also increased. Within one year of treatment many of the trees died. The trees that were treated with 48 kg ammonium-N ha(-1) year(-1) did not show any signs of deterioration.
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http://dx.doi.org/10.1016/0269-7491(90)90102-i | DOI Listing |
FEMS Microbiol Ecol
August 2005
Department of Biological and Environmental Sciences, Division of General Microbiology, FIN-00014 University of Helsinki, Finland.
A new approach, in which ammonia-oxidizing bacteria (AOB) are entrapped from soil onto cation-exchange membranes, was applied to identify terrestrial AOB by fluorescence in situ hybridization (FISH). An experimental hot spot of ammonia oxidation was developed by establishing a gradient of ammonium substrate (200 to <20 mg NH4+-N l(-1)) diffused through the cation-exchange membranes incubated in soil for 6 months. By this approach we were able to characterise and image indigenous AOB populations growing in heavily oil-polluted soil using FISH and sequence analysis of PCR-amplified 16S rRNA genes, respectively.
View Article and Find Full Text PDFEnviron Pollut
August 2004
Department of Aquatic Ecology and Biogeology, Faculty of Science, Catholic University, Toernooiveld, NL-6525 ED Nijmegen, The Netherlands.
To obtain an insight into the effects of a high ammonium deposition on trees young, coniferous trees were planted in pots in a greenhouse and treated with artificial ammonium-enriched rainwater. Application of 480 kg ammonium N ha(-1) year(-1) resulted in an increase of the shoot/root ratio. The biomass of fine roots strongly declined, as did the numbers of mycorrhizae.
View Article and Find Full Text PDFEnviron Pollut
October 2004
Department of Aquatic Ecology and Biogeology, Faculty of Science, Catholic University, Toernooiveld, NL-6525 ED Nijmegen, The Netherlands.
A pot experiment was used to investigate whether ammonium sulphate, when applied in amounts comparable to those deposited in the Dutch forests, is detrimental to trees. Young coniferous trees were planted in pots and treated with artificial ammonium-enriched rainwater in a greenhouse. The deposition of ammonium resulted in a strong acidification of the soil solution, leaching of base cations and an increased solubility of aluminium, manganese and zinc.
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