Relação entre grupos de árvores de dossel com liteira de alta e baixa qualidade e a ciclagem de nutrientes em terra firme na Amazônia Central

Abstract

The high nutritional quality of leaves is indicated by a low C/N ratio and leaves with low nutritional quality by high C/N ratio. In this study six species of litter were used: three species considered to have good nutritional quality and rapid decomposition and three with low quality and slow decomposition. The study aimed to verify differences in decomposition, nutrient release, nutrient concentrations in the soil beneath these trees and the existence of a differential macrofauna in the two litter groups. Weight loss showed the expected results, except for one species, indicating that other factors are acting in addition to C/N ratio and lignin percentage. The amounts of calcium increased in decomposing leaves continuously during the experiment, indicating a relative rise, or even result of translocation of Ca from fungal hyphae and/or by soil fauna. The amounts of magnesium, potassium and phosphorus should standard results, with higher losses in the rainy season. The element released faster to soil was potassium. The nutrients determinations in the soil below the chosen species and its relation with the species nutrients showed no significant values. The differences between species for the percentage of remaining weight, and the lack of correlation between the species and soil nutrients, indicate the importance of high trees diversity and proximity in the Amazon forest for controlling nutrient cycling.