Nitrous oxide emissions from forests and pastures of various ages in the Brazilian Amazon

Melillo, Jerry M.; Steudler, Paul A.; Feigl, Brigitte Josefine; Neill, Christopher; García, Diosdado Baena; Píccolo, Marisa de Cássia; Cerri, Carlos Clemente; Tian, H.

doi:10.1029/2000jd000036

Cited by 132 publications

(132 citation statements)

References 33 publications

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“…Alguns autores, tais como Neill et al (1995, 1997) e Verchot et al (1999, mostraram que a quantidade de N que cicla nas pastagens é bem menor quando comparadas com valores observados nas florestas. A mesma pastagem do presente estudo revelou, em trabalhos anteriores, baixas taxas de emissão de N 2 O medidos no campo (Verchot et al, 1999;GarciaMontiel et al, 2001;Melillo et al, 2001). …”

Section: Resultsunclassified

“…Emissões de N 2 O no período seco nesta pastagem e em outras pastagens estabelecidas na Nova Vida variam, na maioria das vezes, de -10 a 20 µg m -2 h -1 de N (Garcia- Montiel et al, 2001;Melillo et al, 2001;Passianoto et al, 2003). Experimentos com solo irrigado em duas pastagens da Nova Vida durante um período muito seco do ano produziram pequenos incrementos nos fluxos de N 2 O, passando de 10,2 para 30,6 µg m -2 h -1 , vinte minutos após a adição de água, tendo retornado aos valores iniciais 5 h depois (Garcia-Montiel et al, 2003 Com relação ao potencial de nitrificação dos solos em questão, aparentemente os dados permitem afirmar que este potencial é realmente baixo em solos sob pastagem na Amazônia.…”

Section: Resultsunclassified

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Disponibilidade de nitrogênio e fluxos de N2O a partir de solo sob pastagem após aplicação de herbicida

Carmo

Andrade

Cerri³

et al. 2005

Rev. Bras. Ciênc. Solo

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Section: Resultsunclassified

Disponibilidade de nitrogênio e fluxos de N2O a partir de solo sob pastagem após aplicação de herbicida

Carmo

Andrade

Cerri³

et al. 2005

Rev. Bras. Ciênc. Solo

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“…b Modeled for sub-Saharan Africa after Bouwman et al (2002), N input in agroecosystems derived by Potter et al (2010), Edgar 4.1 data for natural emissions from countries of North Africa, based on IPCC methodology (Hickman et al, 2011). c empirical equation base on published data (Keller, 1993;Weitz et al, 1998;Verchot et al, 1999;Potter et al, 2001;Melillo et al, 2001;Neill et al, 2005;Verchot et al, 2006;Mapanda et al, 2010). wetlands and saturated soils, anaerobic hotspots in unsaturated soils, mostly associated to organic input and intense mineralization activity.…”

Section: N 2 O and Ch 4 Fluxes From Biogenic Sources And Firesmentioning

confidence: 99%

A full greenhouse gases budget of Africa: synthesis, uncertainties, and vulnerabilities

et al. 2014

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Abstract. This paper, developed under the framework of the RECCAP initiative, aims at providing improved estimates of the carbon and GHG (CO 2 , CH 4 and N 2 O) balance of continental Africa. The various components and processes of the African carbon and GHG budget are considered, existing data reviewed, and new data from different methodologies (inventories, ecosystem flux measurements, models, and atmospheric inversions) presented. Uncertainties are quantified and current gaps and weaknesses in knowledge and monitoring systems described in order to guide future requirements. The majority of results agree that Africa is a small sink of carbon on an annual scale, with an average value of Published by Copernicus Publications on behalf of the European Geosciences Union. R. Valentini et al.: A full greenhouse gases budget of Africa−0.61 ± 0.58 Pg C yr −1 . Nevertheless, the emissions of CH 4 and N 2 O may turn Africa into a net source of radiative forcing in CO 2 equivalent terms. At sub-regional level, there is significant spatial variability in both sources and sinks, due to the diversity of biomes represented and differences in the degree of anthropic impacts. Southern Africa is the main source region; while central Africa, with its evergreen tropical forests, is the main sink. Emissions from land-use change in Africa are significant (around 0.32 ± 0.05 Pg C yr −1 ), even higher than the fossil fuel emissions: this is a unique feature among all the continents. There could be significant carbon losses from forest land even without deforestation, resulting from the impact of selective logging. Fires play a significant role in the African carbon cycle, with 1.03 ± 0.22 Pg C yr −1 of carbon emissions, and 90 % originating in savannas and dry woodlands. A large portion of the wild fire emissions are compensated by CO 2 uptake during the growing season, but an uncertain fraction of the emission from wood harvested for domestic use is not. Most of these fluxes have large interannual variability, on the order of ±0.5 Pg C yr −1 in standard deviation, accounting for around 25 % of the year-toyear variation in the global carbon budget.Despite the high uncertainty, the estimates provided in this paper show the important role that Africa plays in the global carbon cycle, both in terms of absolute contribution, and as a key source of interannual variability.

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“…All free-living N fixation rate data used in our analyses were originally obtained using the acetylene reduction assay (Burns and Hardy 1975). N losses N can be lost from ecosystems via erosion, fire, or biomass removal, but gaseous emissions and export to streams are the principal mechanisms of N loss from primary tropical rain forests (Chestnut et al 1999;Melillo et al 2001;Markewitz et al 2004;Neill et al 2006). Hydrological N losses-N lost along the continuum from soils to streams-were calculated from the literature, with an emphasis on data obtained from the forest at Rancho Grande.…”

Section: N Inputsmentioning

confidence: 99%

Using indirect methods to constrain symbiotic nitrogen fixation rates: a case study from an Amazonian rain forest

et al. 2009

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Human activities have profoundly altered the global nitrogen (N) cycle. Increases in anthropogenic N have had multiple effects on the atmosphere, on terrestrial, freshwater and marine ecosystems, and even on human health. Unfortunately, methodological limitations challenge our ability to directly measure natural N inputs via biological N fixation (BNF)-the largest natural source of new N to ecosystems. This confounds efforts to quantify the extent of anthropogenic perturbation to the N cycle. To address this gap, we used a pair of indirect methods-analytical modeling and N balance-to generate independent estimates of BNF in a presumed hotspot of N fixation, a tropical rain forest site in central Rondônia in the Brazilian Amazon Basin. Our objectives were to attempt to constrain symbiotic N fixation rates in this site using indirect methods, and to assess strengths and weaknesses of this approach by looking for areas of convergence and disagreement between the estimates. This approach yielded two remarkably similar estimates of N fixation. However, when compared to a previously published bottom-up estimate, our analysis indicated much lower N inputs via symbiotic BNF in the Rondônia site than has been suggested for the tropics as a whole. This discrepancy may reflect errors associated with extrapolating bottom-up fluxes from plot-scale measures, those resulting from the indirect analyses, and/or the relatively low abundance of legumes at the Rondônia site. While indirect methods have some limitations, we suggest that until the technological challenges of directly measuring N fixation are overcome, integrated approaches that employ a combination of

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Nitrous oxide emissions from forests and pastures of various ages in the Brazilian Amazon

Cited by 132 publications

References 33 publications

Disponibilidade de nitrogênio e fluxos de N2O a partir de solo sob pastagem após aplicação de herbicida

Disponibilidade de nitrogênio e fluxos de N2O a partir de solo sob pastagem após aplicação de herbicida

A full greenhouse gases budget of Africa: synthesis, uncertainties, and vulnerabilities

Using indirect methods to constrain symbiotic nitrogen fixation rates: a case study from an Amazonian rain forest

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