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Martinson, G.; Corre, M. & Veldkamp, E. (2012): Responses of nitrous oxide fluxes and soil nitrogen cycling to nutrient additions in montane forests along an elevation gradient in southern Ecuador. Biogeochemistry online , online
DOI: http://dx.doi.org/10.1007/s10533-012-9753-9.

Resource Description

Title: Responses of nitrous oxide fluxes and soil nitrogen cycling to nutrient additions in montane forests along an elevation gradient in southern Ecuador
FOR816dw ID: 1151
Publication Date: 2012-06-27
License and Usage Rights: http://www.tropicalmountainforest.org/dataagreement.do
Resource Owner(s):
Individual: Guntars Martinson
Contact:
Individual: Marife Corre
Contact:
Individual: Edzo Veldkamp
Contact:
Abstract:
Tropical montane forests are commonly limited by N or co-limited by N and P. Projected increases in N deposition in tropical montane regions are thought to be insufficient for vegetation demand and are not therefore expected to affect soil N availability and N2O emissions. We established a factorial Nand P-addition experiment (i.e., N, P, N ? P, and control) across an elevation gradient of montane forests in Ecuador to test these hypotheses: (1) moderate rates of N and P additions are able to stimulate soil-N cycling rates and N2O fluxes, and (2) the magnitude and timing of soil N2O-flux responses depend on the initial nutrient status of the forest soils. Moderate rates of nutrients were added: 50 kg N ha-1 year-1 (in the form of urea) and 10 kg P ha-1 year-1 (in the form of NaH2PO4 . 2H2O) split in two equal applications. We tested the hypotheses by measuring changes in net rates of soil–N cycling and N2O fluxes during the first 2 years (2008??2009) of nutrient manipulation in an oldgrowth premontane forest at 1,000 m, growing on a Cambisol soil with no organic layer, in an old-growth lower montane forest at 2,000 m, growing on a Cambisol soil with an organic layer, and an oldgrowth upper montane rainforest at 3,000 m, growing on a Histosol soil with a thick organic layer. Among the control plots, net nitrification rates were largest at the 1,000-m site whereas net nitrification was not detectable at the 2,000and 3,000-m sites. The already large net nitrification at the 1,000-m site was not affected by nutrient additions, but net nitrification became detectable at the 2,000and 3000-m sites after the second year of N and N + P additions. N2O emissions increased rapidly following N and N ? P additions at the 1,000-m site whereas only smaller increases occurred at the 2,000and 3,000-m sites during the second year of N and N + P additions. Addition of P alone had no effect on net rates of soil N cycling and N2O fluxes at any elevation. Our results showed that the initial soil N status, which may also be influenced by presence or absence of organic layer, soil moisture and temperature as encompassed by the elevation gradient, is a good indicator of how soil N cycling and N2O fluxes may respond to future increases in nutrient additions.
Additional Infos:
online first
Keywords:
| phosphorus | mountain forest | N2O emissions | soil N availability | nutrient manipulation | nutrient limitation | wood specific gravity | aboveground biomass | environmental gradients | carbon stocks | Pilodyn wood tester |
Literature type specific fields:
ARTICLE
Journal: Biogeochemistry
Volume: online
Page Range: online
Metadata Provider:
Individual: Guntars Martinson
Contact:
Online Distribution:
Download File: http://www.tropicalmountainforest.org/publications.do?citid=1151

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