Can topography affect the restoration of soil properties after deforestation in a semiarid ecosystem?

摘要

The use of vegetation as a source of energy and its clearing for agricultural production has contributed to the degradation of the drylands in world. On soil, the effects of deforestation are still controversial and need to be better understood. In this study, the effect of deforestation and soil topography on soil morphological properties, nutrient availability, and carbon (C) contribution in a topossequence that was deforested 12 years before in the Brazilian semi-arid region was evaluated. For this purpose, two areas (preserved and deforested) were selected and separated into three positions along the slope: lower, middle, and upper third. For each position, the characterization of the soil fertility and the physical and morphological attributes of the selected profiles were carried out. In general, deforestation had no effect on the total organic carbon (TOC) of the soil, but, on the other hand, was responsible for increasing the structural fragility of the soil. The major effect of deforestation on soil fertility was reduced availability of cationic nutrients (Mg2+ and K+). We conclude that topography had no effect on the restoration of soil properties after deforestation in this semiarid ecosystem. For these conditions, similar management strategies (e.g. reforestation), can be adopted for the different topographical positions of the slope. Our results can be used in forest restoration projects of degraded ecosystems in drylands, to select the best practices of management, aiming at restoring the natural ecological processes of the ecosystem.