Caracterização de substâncias húmicas em uma topossequência na ilha de Algodoal/ Maiandeua-Pa

Abstract

During the intermediate processes of decomposition of organic matter (O.M.) occurs the formation of compounds of heterogeneous and complex nature, called Humic Substances (HS), where we can mention the Humic Acids (H.A.) and Fulvic Acids (FA). The SH characterization study aims to determine the contents of HA and FA in different soil types along a topossequence in AlgodoallMindeaua-PA. The samples were collected at depths 0-5cm, 5-10cm and 10-20cm, stored in refrigerator, then divided into subsamples and analyzed in the laboratory. There was a higher content of FA in the samples studied in relation to HA. The percentage of HA and AF were distributed as follows along the topossequence: Profile 06 = HA (2%, 0.5% and 0.5%), AF (98%, 99.5% and 99.5%). Profile 5A = AH (1%,1% and 1%), AF (99%, 99% and 99%); Profile 05 = AH (2%, 1% and 0.5%), AF (98%, 99% and 99.5%); Profile 4A = AH (2.5%, 2.5% and 0.5%) AF (97.5%,97.5% and 99.5%); Profile 04 = AH (3%, 3% and 1%) AF (97%, 97% and 99%). There is a tendency for the FA contents to increase in depth and the HA contents to decrease in depth. With these values it can be concluded that the higher amount of FA found along the topossequence is due to the acidity of the soils studied and the quality of organic matter available in the soils.