Estoque de carbono e nitrogênio em áreas de vegetação nativa e antropizada no município de Irecê

Abstract

In recent years the Caatinga vegetation increased from 68% to 47%, and disturbed areas grew from 32% to 53% of the total area of the Biome Caatinga. The increasing conversion of natural ecosystems into agroecosystems, with reduced coverage of native vegetation in the semiarid Northeast has led to degradation of natural resources, causing significant changes in natural fertility and organic matter dynamics of soil. The different practices adopted influence directly in the stocks of carbon and nitrogen. Thus, the main objective of the research was to evaluate the changes in carbon stocks and soil nitrogen and biological activity, depending on the agricultural use and human disturbance of Caatinga. The study was conducted in a Cambisol clayey in the municipality of Irecê-Ba (11° 18' 58,44" S e 47° 49' 48,11" W). Samples were collected in three areas (Native Caatinga, Caatinga grass pasture and castor integrated with pasture) at four depths (0-5, 5-10, 10-20 and 20-40 cm). The attributes evaluated were the chemical, physical and microbiological. We evaluated the chemical, physical and microbiological. The results indicate that the change of use in the study areas are contributing to changes that occur in the patterns of soil physical (bulk density and porosity); carbon from the soil microbial biomass was not a good indication of changes use and soil management. There were variations in C stocks between areas grazed Caatinga (45.05 Mg ha-1), Caatinga native (54.06 Mg ha-1) and castor / pasture (52.82 Mg ha-1), for N-total, the highest accumulation occurred in the deeper soil layers, although no change in N-total stocks between management systems.