Study of nutrient dynamics in floodplain soils of the Careiro Island - central Amazonia

Abstract

In contrast to the upland "terra firme' terrain, the floodplain varzea 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 varzea. 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 varzea were always higher than in the high varzea. This could be a result of the deposition effect during former flood periods, because the low varzea is exposed more to seasonal flooding. The study of the main nutrients analysed in the varzea floodplain soils shows a high natural fertility. -English summary