Os solos das áreas de campos da região bragantina, estado do Pará.

Abstract

The Bragantina Region, area with a plane to light wavy relief, in the main part of Quaternary geology, with a annual precipitaiion wariing between 2.091 and 2.77U mm, diverging of forestry secondary cover, presents the following phyto - sociological formations; a) Equatorial sandy field (campina); b) Equatorial sandy bushy field (carrasco); c) Equatorial savannah; and d) Equatorial hydrophyl holm field( campo de varzea). In equatorial sandy fields and equatorial sandy bushy fields, the Quartzy Distrophic Sands and Ground Water Podzol appear. In equatorial savannah, the Yellow Latosol médium texture is present, and in equatorial hydrophyl holm field, Humic Gley and Low Huraic Cley appear. Studying the analitic date of these soils it was possible verify that the pH varies between 3.5 in Humic Gley and Low Humic Gley and 5.7 in Distrophic Quartzy Sandy. In Yellow Latossol, médium texture, the pH varies between 4.0 and 4,6. The organic matter appears with high values only, frist in Humic Gley(11,35%), following the Low Humic GleyC9.5%). Also it was observed that the Humic Gley and Low Humic Gley have high activity clay. All the soils present low sum of bases, low saturation of bases, high saturations of aluminium, unbalance in relations CaVMg, CaVK, Ca+Mg/K and such low assimilable phosphorus. Also the results of laterization complex has show the migration of SIO2 in depth, in profile.