Biomassa e sazonalidade das raízes finas em savanas da Amazônia Oriental

The objective of this work was to compare the biomass of fine roots in different physiognomies evaluating the influence of seasonality at the Amazon savannas located in Amapa and Para States. Soil samples were collected in five positions, from 10 to 50 cm deep. Three points were allocated at typical savanna (Cerrado sensu stricto), 4 at open savanna (Campo Cerrado) and 2 at natural grassland (Campo Limpo). At each point 4 replications were performed. The influence of seasonality was verified only in Campo Cerrado in April (rainfall peak), July (end of rainy season) and October (peak of drought) of 2010 and in January of 2011 (beginning of rainy season). The physiognomies were differentiated by root mass when analyzed under different diametric classes of roots and different depths. The largest mass of fine roots occurred at the peak of the dry season. These results suggest different strategies in finest roots allocation in different physiognomies and soil depths and differences of roots dynamics to increase absorption potential during dry season.