Avaliacao dos compartimentos da materia organica em area de Mata Atlantica

Assessment of organic matter compartments in an Atlantic Forest area. This study has as objective to evaluate the soil organic matter (SOM) compartments in areas with different vegetables coverings in the around of Serra do Mar State Park, Ubatuba, Sao Paulo State. Were selected areas of cassava (monoculture), banana (agroforest system), scrub and secondary forest (Atlantic Forest) and samples of soil were taken at 0-5 and 5-10 cm depths in July 2003 (winter) and March 2004 (summer). Were quantified the total organic carbon (TOC), the humic substances with tenors of organic carbon in the fulvic acid fraction (C-FAF); humic acid fraction (C-HAF) and humin (C-HUM) and the C-FAH/C-FAF ratio and the light organic matter (LOM). The tenors of COT varied between 26.3-35.7 g [kg.sup.-1] and 20.2-33.1 g [kg.sup.-1], 0-5 and 5-10 cm depth, respectively. The tenors of COT were similar between the forest and banana areas. The tenors of MOL were similar between the banana and scrub areas. For the humic substances, the C-HUM predominated and presented small variation between coverings, followed by C-FAF, which was lesser in the banana and cassava areas and C-HAF with small tenors in the cassava area.