Influence of water of the Rio Pará estuary on soil fertility of várzea islands in Belém, Pará

Abstract

The Pará River is an immense estuary formed by numerous rivers and bays, composing a large body of fresh water that flows into the ocean. In this environment, there are many islands, of which 39 belong to the city of Belém. These islands have a small percentage of terra firma, including areas cultivated by family farmers. The objective of this study was to evaluate the effect of the water movement of the Pará River estuary on soil fertility of islands of Belém, Pará. Sampling was carried out on 23 islands in a várzea ecosystem with an area greater than 10 ha, including three significantly large islands (Mosqueiro, Caratateua and Cotijuba) and three islands (Mutum, Santa Rosa and João Pilatos) that belong to the municipality of Ananindeua, located south of Mosqueiro. The samples were collected in a riverine environment, surrounding the islands, with the goal of better understanding the areas used by the local population. The study indicates that there is variability in the soil fertility of insular environments of Belém, including a significant difference between the archipelagos evaluated for calcium (Ca+2), magnesium (Mg+2), potassium (K+) and aluminum (A+3), as well as the sum of bases (SB) and cation exchange capacity (CTC). No significant difference was observed for the values of available phosphorus (P). A gradient in the south-north direction was also observed for the elements K+, Mg+2 and Al+3.

Keywords

• Hidrografia
• Nutrientes
• Várzea