Quality of Soil Organic Matter and Nitrogen and Carbon Stocks in Fragment Atlantic Municipality Neopolis, Sergipe.

Abstract

Native forests are important environments for the protection of biodiversity, hydrology and soil conditions. Soils under native vegetation express their full potential through their physical, chemical and biological attributes, which are of great qualitative value for plant development and C accumulation. Soil environment represents one the major terrestrial C pool, having great capacity to sequester C from the atmosphere. Soil organic matter is one of the most important indicators of soil quality and it is commonly used to access impacts caused by management practices. The present study aimed to evaluate organic matter physical fractions as indicator of soil quality as well as the capacity for C and N sequestration of a Yellow Ultisol, under native forest, in Neópolis county, Sergipe. Soil organic matter fractions were classified as particulate organic matter (POM) and complexed organic matter (COM) through physical fractionation method. Carbon was determined in the soil as well as in the fractions, while Nitrogen was only determined in the soil. Soil C and N stocks were calculated based on soil bulk density and on the thickness of sampled soil layers. Carbon concentrations were higher in the complexed organic matter fraction than in the particulate fraction, possibly as a result of the great humification rate, a very common trend in forests soil. Carbon and N stocks were higher in the subsurface than in the surface layer, a result of the thickness of the layer as well as great level of physical and chemical protection.