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Impact of elevated N input on soil N cycling and losses in old-growth lowland and montane forests in Panama

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dc.contributor.author Corre, Marife D. en
dc.contributor.author Veldkamp, Edzo en
dc.contributor.author Arnold, Julia en
dc.contributor.author Wright, S. Joseph en
dc.date.accessioned 2010-11-16T21:20:31Z
dc.date.available 2010-11-16T21:20:31Z
dc.date.issued 2010
dc.identifier.citation Corre, Marife D., Veldkamp, Edzo, Arnold, Julia, and Wright, S. Joseph. 2010. "<a href="https%3A%2F%2Frepository.si.edu%2Fhandle%2F10088%2F11138">Impact of elevated N input on soil N cycling and losses in old-growth lowland and montane forests in Panama</a>." <em>Ecology</em>. 91 (6):1715&ndash;1729. <a href="https://doi.org/10.1890/09-0274.1">https://doi.org/10.1890/09-0274.1</a> en
dc.identifier.issn 0012-9658
dc.identifier.uri http://hdl.handle.net/10088/11138
dc.description.abstract Nitrogen deposition is projected to increase rapidly in tropical ecosystems, but changes in soil-N-cycling processes in tropical ecosystems under elevated N input are less well understood. We used N-addition experiments to achieve N-enriched conditions in mixedspecies, lowland and montane forests in Panama. Our objectives were to (1) assess changes in soil mineral N production (gross rates of N mineralization and nitrification) and retention (microbial immobilization and rapid reactions to organic N) during 1- and 9-yr N additions in the lowland forest and during 1-yr N addition in the montane forest and (2) relate these changes to N leaching and N-oxide emissions. In the old-growth lowland forest located on an Inceptisol, with high base saturation and net primary production not limited by N, there was no immediate effect of first-year N addition on gross rates of mineral-N production and N-oxide emissions. Changes in soil-N processes were only apparent in chronic (9 yr) N-addition plots: gross N mineralization and nitrification rates, NO3 leaching, and N-oxide emissions increased, while microbial biomass and NH4 þ immobilization rates decreased compared to the control. Increased mineral-N production under chronic N addition was paralleled by increased substrate quality (e.g., reduced C:N ratios of litterfall), while the decrease in microbial biomass was possibly due to an increase in soil acidity. An increase in N losses was reflected in the increase in 15N signatures of litterfall under chronic N addition. In contrast, the old-growth montane forest located on an Andisol, with low base saturation and aboveground net primary production limited by N, reacted to first-year N addition with increases in gross rates of mineral-N production, microbial biomass, NO3 leaching, and Noxide emissions compared to the control. The increased N-oxide emissions were attributed to increased nitrification activity in the organic layer, and the high NO3 availability combined with the high rainfall on this sandy loam soil facilitated the instantaneous increase in NO3 eaching. These results suggest that soil type, presence of an organic layer, changes in soil-N cycling, and hydrological properties are more important indicators than vegetation as an N sink on how tropical forests respond to elevated N input. en
dc.relation.ispartof Ecology en
dc.title Impact of elevated N input on soil N cycling and losses in old-growth lowland and montane forests in Panama en
dc.type Journal Article en
dc.identifier.srbnumber 90747
dc.identifier.doi 10.1890/09-0274.1
rft.jtitle Ecology
rft.volume 91
rft.issue 6
rft.spage 1715
rft.epage 1729
dc.description.SIUnit STRI en
dc.citation.spage 1715
dc.citation.epage 1729

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