Impact of pine plantations on the form and mobility of nitrogen in soils of the eastern escarpment region of South Africa

 

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dc.contributor.advisor Willis, James en_ZA
dc.contributor.advisor Fey, Martin V en_ZA
dc.contributor.author Echeverría, Marietta Elena en_ZA
dc.date.accessioned 2014-09-25T08:47:33Z
dc.date.available 2014-09-25T08:47:33Z
dc.date.issued 2000 en_ZA
dc.identifier.citation Echeverría, M. 2000. Impact of pine plantations on the form and mobility of nitrogen in soils of the eastern escarpment region of South Africa. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/7680
dc.description Bibliography: leaves 96-101. en_ZA
dc.description.abstract Recent research in the eastern escarpment area of South Africa has documented enhanced NO₃- concentrations in soil solution and stream water resulting from afforestation. There has been much research in the Northern Hemisphere regarding the qualitative and quantitative causes and consequences of N saturation in forest ecosystems. In order to assess the significance of local observations of afforestation-induced NO₃- enhancement in a global context, a study was conducted to evaluate the influence of forest plantations (Pinus spp.) on N form and mobility in soils in the eastern escarpment area of South Africa. Twenty soil samples were taken, half in grassland and half in forest, in the Graskop and Kaapsehoop areas of the eastern escarpment. Forest samples were taken as composites of approximately five individual samples in each stand from the top 20-25 em of soil, combining partially decomposed organic litter layer with the subjacent upper mineral soil horizon. Grassland samples were taken, again as composites, consisting of the upper mineral soil horizon (an organic litter layer was for the most part absent). Approximately three-quarters of each sample was air-dried, and crushed to pass through a 2-mm sieve and stored for analysis. The remaining quarter of each sample was passed through a 2-mm sieve and refrigerated at about 4°C in order to maintain field-moist conditions and to inhibit microbial transfornlations. Refrigerated samples were used for KCI-extractable NO₃- and NH₄+ analyses and N mineralisation experiments. The remaining analyses were performed on the air-dried samples. This study included two facets: physical and chemical characterisation of soil samples; and a series of laboratory experiments. The solid phase of the soils was analysed for organic carbon, total nitrogen and particle size distribution. The soil solution was investigated by making saturated paste extracts which were analysed for major ions, trace elements, electrical conductivity (EC) and pH. Extractable base cations, acidity and inorganic nitrogen (NH₄+ and NO₃-) were also analysed after extraction with NH₄OAc or KCl solutions. The laboratory experiments, intended to investigate the apparent differences in soil N transformations and mobility resulting from vegetation, consisted of both aerobic and anaerobic incubation to assess N mineralisation, a NO₃- sorption experiment and a soil to extract ratio dilution experiment. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Environmental Geochemistry en_ZA
dc.title Impact of pine plantations on the form and mobility of nitrogen in soils of the eastern escarpment region of South Africa en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Geological Sciences en_ZA
dc.type.qualificationlevel Masters en_ZA
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image


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