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| Author(s): |
Cleber Ibraim Salimon
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB) |
| Defense date: | 2003-05-14 |
| Examining board members: |
Reynaldo Luiz Victoria;
Brigitte Josefine Feigl;
Carlos Augusto Klink;
Humberto Ribeiro da Rocha;
José Eduardo dos Santos
|
| Advisor: | Reynaldo Luiz Victoria |
| Abstract | |
Conversion of forest to cattle pastures and subsequent abandonment of those pastures is occurring throughout the Amazon Basin, but the biogeochemical consequences of this land cover change are not well understood. In this study we assess the effects of land-use change on soil respiration in pastures, secondary forests and mature forests near Rio Branco, Acre. Leaves inside the measurement chambers were responsible for about 50% of the pasture fluxes in the wet season, but in the dry season its influence was confounded with variability within replicates. The greatest CO2 fluxes are observed in pastures, which also presented the greatest amplitude of seasonal variation. Annual fluxes were 20% higher in pastures compared to forests. Heterotrophic respiration was similar in pasture and mature and secondary forests, indicating that autotrophic respiration is probably the main cause of higher fluxes in pastures. The ?13C of heterotrophic respired CO2 in pasture was -15, showing that microorganisms in pasture soil are feeding mostly on carbon from grasses and not from remaining forest carbon. (AU) | |
| FAPESP's process: | 99/03315-3 - Flux of carbon between soil and atmosphere in a chronosequence in Western Amazonia (Acre) |
| Grantee: | Cleber Ibraim Salimon |
| Support Opportunities: | Scholarships in Brazil - Doctorate |