Recupera？？o de solos degradados na explora？？o mineral de cassiterita: biomassa microbiana e atividade da desidrogenase

the evaluation of the environmental quality assumes great importance in recovery programs of degraded areas, which makes necessary the development of quantitative systems based on combinations of indicators that best represent the degradation or the ongoing recovery conditions. this work uses soil biological parameters, such as microbian biomass and dehydrogenase activity, in addition to the analysis of the plant material to verify the influence of the successive planting of legumes in a mined soil undergoing recovery. the microbian activity was determined through the quantification of the microbian biomass' carbon and nitrogen (bmc e bmn), the dehydrogenase activity and fda hydrolysis, evaluated in a mine pit area after one, two and three years of consecutive planting of legumes, and in a tailing area after one year of planting a mixture of legumes (pigeon peas, velvet beans and sunn hemp). those areas were compared to forest soil and areas with no planting. the use of biological indicators (microbian biomass and dehydrogenase activity) and the analysis of plant material in the evaluation of the adopted techniques and strategies revealed that the planting of legumes and its further incorporation promoted positive and gradual modifications in the degraded soil, mainly in the bmc in areas after the consecutive planting of legumes over the course of three years.