Abstract
In contrast to the upland "terra firme" terrain, the floodplain várzea in the Amazon is the zone that is
used for supporting rational agriculture without use of fertilizers. Following the dynamics of the main soil
nutrients, two distinct floodplain environments were selected, namely high and low várzea. Soil samples
were collected throughout the whole year of 1987. No significant differences were found in the concentrations of the main nutrients for samples taken during different periods. However, the concentrations of Ca,
Mg, Na, Al, H, Cu, Zn and Mn in the low várzea were always higher than in the high várzea. This could
be a result of the deposition effect during former flood periods, because the low várzea is exposed more
to seasonal flooding. The study of the main nutrients analysed in the várzea floodplain soils shows a high
natural fertility.
