Cite as:
Wullaert, H.; Homeier, J.; Valarezo, C. &amp; Wilcke, W. (2010): <b>Response of the N and P cycles of an old-growth montane forest in Ecuador to experimental low-level N and P amendments</b>. <i>Forest Ecology and Management</i> <b>260</b>, 1435-1445.

Resource Description

Title: Response of the N and P cycles of an old-growth montane forest in Ecuador to experimental low-level N and P amendments
Short Name: N and P addition (NUMEX)
FOR816dw ID: 903
Publication Date: 2010-09-30
License and Usage Rights:
Resource Owner(s):
Individual: Hans Wullaert
Individual: Jürgen Homeier
Individual: Carlos Valarezo
Individual: Wolfgang Wilcke
Atmospheric nitrogen (N) and phosphorus (P) depositions are expected to increase in the tropics as a<br/> consequence of increasing human activities in the next decades. In the literature, it is frequently assumed<br/> that tropical montane forests are N-limited, while tropical lowland forests are P-limited. In a low-level N<br/> and P addition experiment, we determined the short-term response of N and P cycles in a north Andean<br/> montane forest on Palaeozoic shists and metasandstones at an elevation of 2100m a.s.l. to increased N<br/> and P inputs. We evaluated experimental N, P and N+ P additions (50 kg ha&#8722;1 yr&#8722;1 of N, 10 kg ha&#8722;1 yr&#8722;1<br/> of P and 50 kg + 10 kg ha&#8722;1 yr&#8722;1 of N and P, respectively) and an untreated control in a fourfold replicated<br/> randomized block design. We collected litter leachate, mineral soil solution (0.15 and 0.30m depths),<br/> throughfall and litterfall before the treatment began (August 2007) until 16 months after the first nutrient<br/> application (April 2009). Less than 10 and 1% of the applied N and P, respectively, leached below the<br/> organic layer which contained almost all roots and no significant leaching losses of N and P occurred<br/> to below 0.15m mineral soil depth. Deposited N and P from the atmosphere in dry and wet form were<br/> retained in the canopy of the control treatment using a canopy budget model. Nitrogen and P retention<br/> by the canopy were reduced and N and P fluxes in throughfall and litterfall increased in their respective<br/> treatments. The increase in N and P fluxes in throughfall after fertilization was equivalent to 2.5% of the<br/> applied N and 2% of the applied P. The fluxes of N and P in litterfall were up to 15% and 3%, respectively,<br/> higher in the N and N+ P than in the control treatments. We conclude that the expected elevated N and P<br/> deposition in the tropics will be retained in the ecosystem, at least in the short term and hence, N and P<br/> concentrations in stream water will not increase. Our results suggest that in the studied tropical montane<br/> forest ecosystem on Palaeozoic bedrock, N and P are co-limiting the growth of organisms in the canopy<br/> and organic layer.
| tropical montane forest | nutrient cycle | leaching losses | N deposition | P deposition | environmental change |
Literature type specific fields:
Journal: Forest Ecology and Management
Volume: 260
Page Range: 1435-1445
Publisher: Elsevier B.V.
ISSN: 0378-1127
Metadata Provider:
Individual: Bernhard Runzheimer
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