Data/hora: 08/06/2024 00:49:44

Biblioteca(s): | Embrapa Meio Ambiente.
Data corrente: | 19/01/2015
Data da última atualização: | 20/01/2015
Autoria: | CABRAL, O. M. R.; GASH, J. H. C.; ROCHA, H. R. da; MARSDEN, C.; LIGO, M. A. V.; FREITAS, H. C. de; TATSCH, J. D.; GOMES, E.
Afiliação: | OSVALDO MACHADO RODRIGUES CABRAL, CNPMA; JOHN H GASH, Centre for Ecology and Hydrology; HUMBERTO RIBEIRO DA ROCHA, IAG-USP; CLAIRE MARSDEN, CIRAD; MARCOS ANTONIO VIEIRA LIGO, CNPMA; HELBER CUSTÓDIO DE FREITAS, IAG-USP; JONATAN TATSCH, IAG-USP; EDUARDO GOMES, IAG-USP.
Título: | Fluxes of CO2 above a plantation of Eucalyptus in southeast Brazil.
Ano de publicação: | 2011
Fonte/Imprenta: | Agricultural and Forest Meteorology, v. 151, p. 49?59, 2011.
Idioma: | Inglês
Conteúdo: | Abstract: Eddy-covariance measurements of net ecosystem exchange of CO2 (NEE) and estimates of gross ecosystem productivity (GEP) and ecosystem respiration (RE) were obtained in a 2?4 year old Eucalyptus plantation during two years with very different winter rainfall. In the first (drier) year the annual NEE, GEP and RE were lower than the sums in the second (normal) year, and conversely the total respiratory costs of assimilated carbon were higher in the dry year than in the normal year. Although the net primary production (NPP) in the first year was 23% lower than that of the second year, the decrease in the carbon use efficiency (CUE = NPP/GEP) was 11% and autotrophic respiration utilized more resources in the first, dry year than in the second, normal year. The time variations in NEE were followed by NPP, because in these young Eucalyptus plantations NEE is very largely dominated by NPP, and heterotrophic respiration plays only a relatively minor role. During the dry season a pronounced hysteresis was observed in the relationship between NEE and photosynthetically active radiation, and NEE fluxes were inversely proportional to humidity saturation deficitvalues greater than 0.8 kPa. Nighttime fluxes of CO2 during calm conditions when the friction velocity (u*) was below the threshold (0.25ms?1) were estimated based on a Q10 temperature-dependence relationship adjusted separately for different classes of soil moisture content, which regulated the temperature sensitivity of ecosystem respiration.
Palavras-Chave: | CO2 fluxes; Eucalyptus plantation; Water deficit.
Thesagro: | Dióxido de carbono; Eucalipto.
Thesaurus Nal: | Carbon cycle; Carbon dioxide; Ecosystem respiration; Eddy covariance; Eucalyptus; Net ecosystem exchange.
Categoria do assunto: | P Recursos Naturais, Ciências Ambientais e da Terra
Registro original: | Embrapa Meio Ambiente (CNPMA)
Exemplares: | CNPMA - (13476-1) - UPC - AP - DD -  -  -  - DIS