Avaliação de atributos químicos e biológicos na recuperação de solo minerado na região de Candiota-RS

Abstract

Mining is one of the most destructive economic activities on natural ecosystems. There are about 750 hectares impacted by open pit coal mining located in the Candiota/RS deposit, which is the largest in Brazil, with 1.2 billion tons subject to mining. In soils impacted by mining, the incorporation of litter, linked to the time of restoration and maintenance of vegetation, can present positive correlations with the activity of the edaphic fauna in these areas, mitigating the damage and gradually recovering the ecological functions of the new ecosystem. The objective of the present work was to analyze the effects of revegetation with perennial summer grasses submitted to different mowing managements on the biological and chemical quality of soils degraded by coal mining in an experimental area in the Candiota Reservoir/RS. To carry out the work, analyzes were carried out to count and identify edaphic organisms using modified BerleseTüllgren funnels, and microbiological analyzes to quantify Microbial Biomass Carbon (MBC), Basal Respiration (RB) and Urease enzymatic activity. The different fractions of Soil Organic Matter (fulvic, humic and humin acids) were also quantified to understand the degree of humification in the area. Data were compared in verification of means by Tukey's test (p<0.05) and by Pearson's correlation (p<0.05). After 18 years of revegetation and 11.6 years of management in the area, improvement in CBM and RB can be seen when compared to the reference soil, evidencing the positive effect of the perennial grasses used in the experimental area. However, the management with mowing and permanence of plant biomass on the surface cannot yet be considered the most promising management for the improvement of edaphic conditions and ecological recovery of the area.