ABSTRACT
The vast majority of research on nutrients in natural forest is concentrated in the litter. In Brazil, in Atlantic Forest, some investigations have been conducted in few locations such as Dois Irmãos Forest (PE), Tijuca Forest (RJ) and Salão Dourado Forest (MG). In the present research, the studied area was characterized as remaining of Atlantic Forest classified as slope, ombrofilous forest. The objective was to determine by a phytosociologic study the ten species of most important value (VI) and to evaluate the Ca, Mg, P, K and N nutrients contents in these species leaves, likewise to estimate leaf biomass and the efficiency of biological nutrient utilization, increasing the knowledge about Atlantic Forest residues in Brazil. After determining the ten species of most important value, the largest circumference individuals at 1.30 m from soil surface (CAP) in each specie were sampled and the leaves from the intermediate part of the trees top were collected, making a composed sample, being determined Ca, Mg, P, K and N contents. In this study, the leaf biomass was estimate in each species and, to transform this biomass in kg/ha, the leaf biomasses from the species' individuals were added in the area. The nutrient contents in leaf biomass from the species (kg/ha) were achieved multiplying the content (g/kg) by leaf biomass (kg/ha) in each specie. The biological utilization efficiency was calculated considering the ratio between the leaf biomass and the nutrient contents from species. The leaves nutrient contents were in a decreasing order N>Ca>K>Mg>P, but in some species the K content was higher than Ca content. The leaf biomass of the ten most important value species was 3.3 t ha-1 which represented 24.5 % of the total spot leaf biomass (13.4 t ha-1). Schefflera morototoni (Aubl.) Maguire, Steyerm & Frodin showed the most leaf entrance of Ca e Mg while Helicostylis tomentosa (Poepp. & Endl.) J.F., Macbr. showed the best results for P, K and N in the spot. The biological utilization efficiency presented the sequence P>Mg>K>Ca>N.
Keywords:
native forest; leaf biomass; leaf nutrient content