Nutrientes e carbono no solo e em espécies generalistas e especialistas de platô e baixio na Amazônia central

Abstract

Tropical forest soils are known to have low fertility. Despite this, tropical forests have a vegetation characterized by a great diversity of species and high biomass. A key factor for the regulation of these ecosystems is the efficient cycling of nutrients, currently being an important area of scientific investigation to understand the relationship between soil and vegetation. A large part of the nutrients and carbon (C) available for the forest to function are stored in the soil and forest biomass. In Central Amazonia, variations in topography create environmental gradients with the occurrence of sandy soils and water table depth close to the surface in the valleys , contrasting with high clay content and well drained soils in the plateaus. Thus, in these different environments, species with more specialist behavior can occur, that is, found in only one type of soil, and other species with a more generalist pattern that occur in both environments, and do not show any apparent sensitivity to changes in soil type and water availability. In this sense, the objective of this study was to quantify the concentration of nutrients: nitrogen, phosphorus, potassium, magnesium, calcium and carbon in the different compartments (trunk and leaf) of trees and relate them to the stock of nutrients and carbon in the soils at different depths close to the sample trees. For this, nine species with distinct distribution along the topographic gradient were selected, namely: (Micrandra siphonioide, Tapura lanceolata, Brosimum utile subsp - valley specialists ; Eschweilera tessmannii, Ocotea percurrens, Croton lanjouwensis (also known as Croton matourensis Aubl. ) - plateau specialists; Brosimum rubescens, Scleronema micranthum, Protium hebetatum - generalist species. The results showed that the concentration of nutrients varied according to the different functional groups and in the different compartments. The concentration of nutrients in the vegetation is not directly related to the stock of this nutrient in the soil, there are other factors that need to be studied further in order to understand the behavior of each nutrient in a mature forest of land firm from Central Amazonia.Therefore, this work sought to provide important information on the dynamics of nutrients and carbon in tropical forests, in different soil classes.