Estoques de carbono e nitrogênio em vertissolo e condições socioeconômicas e ambientais na microbacia hidrográfica do Riacho Val Paraíso (PB).

Abstract

The change in soil use leads to major changes in carbon stocks carbon- C and nitrogen - N in the soil and, consequently, the global cycling of these elements. The study was conducted in the watershed of Riacho Val Paraíso (PB), aimed to assess the implications of forms of soil use on carbon stocks ( C ) and nitrogen ( N )in the Watershed Riacho Val Paraiso – PB - Brazil. The soil samples studied,Vertissol, were performed in four replicates (four profiles), at depts0-10, 10-20, 20-30 and 30-40 cm. Selected systems were native vegetation; sparse vegetation, pasture, annual agriculture and permanent agriculture. To assess the socioeconomic and environmental conditions 68 questionnaires according to the methodology of Rocha (1997) were applied, and applied in the form of interviews visits rural communities that are part of the watershed above. Soil samples showed pH values ranging from moderately acid and alkali, high levels of Ca2+, Mg2+, K+ and P. The lowest values of density were presented in the area of native vegetation in relation to the management systems as well as in depth 0-10 cm from the depths of all management systems. The levels and stocks of carbon and nitrogen decreased after the change of native vegetation for agriculture and livestock systems and decreased in relation to the depths analyzed. The agricultural production systems and livestock are playing role of emitting C-CO2 when compared with the native vegetation. The region is in the process of high socioeconomic deterioration, over 50% of commitment. Thus, the conservation management of the soil may become an alternative to mitigate emissions of greenhouse gases, contributing to the sustainability of the household production system.