The influence of water in the relationship between CO2 efflux and soil chemical properties in a terra firme forest
Juliana
Silva de
Souza, INPA, souzajs@hotmail.com
(Presenting)
Regina
Costa
Luizão, INPA, rccl@inpa.gov.br
Flavio
Jesus
Luizão, INPA, fluizao@inpa.gov.br
The relationship between soil CO2 efflux and soil humidity and/or temperature have been extensively explored in the literature. However, studies showing relationship between soil CO2 efflux and soil chemical properties are still few. Taking into account that soil CO2 efflux varies in function of the canopy coverage which in turn is affected by the soil, the use of soil chemical properties in the flux models can be useful. This study aimed to evaluate the relationship between soil chemical properties and the soil CO2 flux in three diferent portions of the topographic gradient (plateau, slope and valley) in a terra firme forest near Manaus. In the plateau, there was significant relationship between soil CO2 efflux and the C (p<0.01; r2=0.373), N (p<0.05; r2=0.175), C:N ratio (p<0.05; r2=0.228), available P (p<0.001; r2=0.518), exchangeable K (p<0.001; r2=0.489), exchangeable Mg (p<0.05; r2=0.171) and potential acidity (p<001; r2=0.281). In the valley soil, it was observed significant relationship between soil CO2 efflux and exchangeable K (p=0.054; r2 = 0.226), exchangeable Ca (p<0.05; r2=0.271) and base saturation (p<0.05; r2=0.364). No significant relationships were observed in the slope soils. All the relationships observed in the plateau soil were positive, contrasting with the inverse relationships observed in valley soils, which can be a consequence of the variation in soil water content in the last case, with a ground water nearest from surface.
Submetido por Juliana Silva Souza em 18-MAR-2004
Tema Científico do LBA: CD (Armazenamento e Trocas de Carbono)