C and N of Aggregates in Soil Under Post-Mining Rehabilitation Employing Different Fertilisers and Cover Crops.

Mining activity results in disruption of the soil and exposure to erosive agents, increasing the oxidation of organic compounds and losses through leaching and erosion. The aim of this study was to evaluate the effects of different types of fertiliser and ground cover, on the organic properties of different classes of soil aggregates in an area under rehabilitation after bauxite mining. Soil samples from the 0 - 20 cm layer were collected in an area under rehabilitation planted with coffee, with organic fertiliser (AC), chemical fertiliser (AQ), chemical + organic fertiliser (AQ + AC) and with no fertiliser (SP), where the ground cover between the rows of coffee was of brachiaria (B), estilosantes (E) or with no plants (SP). The total organic carbon and nitrogen (COT and NT) was determined for three classes of aggregate: macro-aggregates (4.75 to 2.0 mm), meso-agregates (2.00 to 0.25 mm) and micro-aggregates (0.25 to 0.053 mm). The application of different types of fertiliser in the areas of brachiaria (AC/B), from among the evaluated treatments employing fertiliser, was found to contribute most to an increase in the organic properties of the soil.