Role of microbial processes in the functioning (Fe mobilization and redistribution) of a representative tropical soil sequence

摘要

Field studies and laboratory experiments have been performed to determine the main processes and the parameters involved in the weathering and soil evolution in a tropical soil sequence from ferralsols to gleysols. The work considers mainly the redoxinterfaces of a soil sequence located in Brazil, looking at the interactions between minerals - soil organic matter and microorganisms. Results show that the bacterial activity (mainly of iron reducing bacteria, IRB) located at the redox interfaces of the hill-side sequences and under the dependence of water movement, soil organic matter and iron availability is the major agent of these weathering processes.