Carbon and nutrient flows in an Amazonian forest: Fine litter production and composition at Apiau, Roraima, Brazil

Abstract

Production and nutrient composition of litter in an Amazonian tropical moist terra firme (upland) forest in Roraima, Brazil, was recorded over 12 months during 1988-89. Total production was 9.17 t ha-1 year- 1 composed of 5.57 t ha-1 year-1 of leaves, 2.43 t ha-1 year-1 of woody material, 0.28 t ha-1 year-1 of reproductive structures, and 0.89 t ha- 1 year-1 of unclassified material. Of the total litter, carbon represented 45.6%. Concentrations of nitrogen (1.51%), calcium (0.61%), and magnesium (0.15%) are similar to those of other tropical forest reports in Brazilian Amazonia. However, concentrations of phosphorus (0.06%) and potassium (0.44%) are among the highest levels recorded in the region. Production of potassium in the leaf fraction and in the total litter, and phosphorus in the leaves, are negatively correlated with precipitation. Mean daily production of leaves differs significantly between wet and dry seasons. Nitrogen and carbon produced in the leaf fraction also vary between wet and dry seasons, as well as calcium in the woody fraction and in unclassified material. A positive correlation exists separately between total litter production and leaf fractions, woody material and unclassified material.