Ecosystem Catalysis: Soil Urease Activity and Grazing in the Serengeti Ecosystem
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Date
1997
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
The activity of soil ureases was evaluated in the laboratory in soils from three
locations in the Serengeti National Park, Tanzania, differing in the grazing intensities
that the grasslands there support. Urease activity was assayed by the instantaneous
release of NH4 as soon as soils drained to field capacity after application of an
aqueous urea solution approximating N concentrations in ungulate urine. The
appearance of NO3 and S04 in extracts was used as an index of biological activity
and pH changes; neither responded to urea addition. Ammonium appearance in
extracts of soils to which water but not urea was applied was low and identical;
appearance in extracts where urea had been added was high and differed between
sites, increasing with the level of grazer activity at a site. The data document
ecologically meaningful levels of soil urease in Serengeti soils and a positive associa-
tion of those levels with grazing intensity.
Description
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Keywords
Citation
McNaughton, S.J., Zuniga, G., McNaughton, M.M. and Banyikwa, F.F., 1997. Ecosystem catalysis: soil urease activity and grazing in the Serengeti ecosystem. Oikos, pp.467-469.