Influência de variáveis biofísicas nas taxas de respiração de solos em floresta tropical da Amazônia Oriental

• Autor(a) principal: Gonçalves, Paulo Henrique Lopes
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5233
• topic: Respiração de solo; Floresta Amazônica; Variáveis meteorológicas; Soil respiration; Amazon forest; Meteorological variables; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA::MICROMETEOROLOGIA

The Amazon rainforest has great biological diversity and it is among the most complex forest ecosystems of the planet. Any forest system is composed of physical components (climatic, edaphic, topographical and among others) and by biological components (animals and plants). Because of the interdependence of these components it is difficult to understand the functioning of the system as a whole. Despite the Amazon forest being the largest continuous reserve of tropical rainforest in the world, there is still little understanding about its functioning, particularly in relation to the carbon cycle. Recent studies have demonstrated the importance of carbon stocks in the soil as a source and potential sink of CO2. However, few experimental studies have been conducted on the quantification of these fluxes and their seasonal variations associated with biophysical variables that influence the magnitude of these fluxes. The objectives of this study are: a) To analyze the seasonal variations of soil rates of respiration with litter in areas of black soil (TP) and yellow Oxisol (LA); b) To identify the function of dependency between the soil respiration rates at the soil surface, with soil temperature, soil moisture and litter production; c) To make a comparation of flux estimates of soil allocated carbon in sites of black soil and yellow Oxisol. The results showed a seasonal variation of the flux soil CO2, the sites of yellow oxisol and black soil in fluxes in both response to the observed seasonality in rainfall, soil temperature and soil moisture. The magnitudes of the CO2 fluxes in the LA site ranged from 1.52 to 3.98 μmol.m-2.s-1 with an average of 2.84 ± 0.20 μmol.m-2.s-1 in LA, while the CO2 fluxes in the TP site ranged from 1.95 to 5.73 μmol.m-2.s-1 and with an average of 3.73 ± 0.35 20 μmol.m-2.s-1. The rainfall in these periods was 37 mm in August and 373 mm in April. The average temperature near the soil surface, in August and April, were 25.3° C and 23.9° C, respectively, while soil moisture ranged from 12.5 % to 21.5 % in respective months. The magnitudes of soil CO2 fluxes, in general, were greater in the rainy season in both experimental sites. The hourly fluxes of soil CO2 in the LA site showed little variation between daytime and night, time in august while in April (rainy season) there was evidence of a diurnal variation. The results of this study indicate a greater allocation of C in TP site compared to the LA site.