Avaliação da recuperação da área degradada pela mineração de argila através do plantio de Mimosa scabrella Benth(Fabaceae), sob duas técnicas de preparação do solo, Doutor Pedrinho, SC

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The reclamation of degraded areas is a set of idealized and executed actions carried out by specialists of the most different areas of the human knowledge seeking to provide the re-establishment of balanced and sustainable conditions existing previouly to the degradation of a natural system. The study area is a mine of refractory clay of 96,14 ha that has been mined by the company Mineração Portobello Ltda. since 1987 and located in Campo Formoso, Doutor Pedrinho, SC, at 904 m of altitude. The original soil is Cambissolo Húmico Alumínico, although the rejects of the mining were used to recompose the topography. The experiment was implanted in January of 2004. The research area was divided in four plots, two of them received the treatment irregular and two the treatment regular. The irregular treatment consisted of opening trenches with approximately 1 m wide, 1,5 m of length and 50 cm of depth with an hydraulic digging machine while the regular treatment consisted to leave the soil surface smooth. In both treatments, 4- 5 months seedlings of Mimosa scabrella (bracaatinga) were transplanted and a 5-10 cm layer of litter added. After 14 months, the species Mimosa scabrella had survival rates higher than 92%, but no significant differences were found between the treatments. For all parameters analysed for Mimosa scabrella development (height, diameter and canopy area), there were significant differences between both techniques of preparation of the terrain, the values being larger in the irregular treatment. Within irregular plot B the largest diameter values (48,16 mm), height (419,33 cm) and canopy area (25.523,85 cm2) were detected. The largest percentage of soil covering (97,13%) was also found in the irregular treatment plot B, being significantly larger when compared to other plots, whose soil cover was around 80%. It was found a high plant species richness, with 151 species and morphospecies being sampled, belonging to 34 botanical families. The families with the larger numbers of species were Asteraceae (39), Poaceae (25), Cyperaceae (20) and Solanaceae (6). The number of exclusive species found within the regular treatment was 57 (54,29%). The index of Sorensen calculated was 0,932, and Jaccard calculated was 0,872, in other words, the regular and irregular treatments shared a high number of plant species. In the irregular plots, the following species of Juncaceae occurred: Juncus cf. capillaceus, Juncus cf. effusus, Juncus cf. microcephalus and Juncus sp. and of Cyperaceae Rhynchospora aurea, Cyperus cf. polystachyos, Cyperus cf. prolixus, which are often found in humid habitats. The efficiency of soil covering should be pointed out considering the short time period that the experiment was conducted. It can be affirmed that there was an effective beginning of recovery of the degradation in a short period of time. The technique to impose the irregular treatment of the terrain was shown to be positive in the sense of stanching the intense erosion of a mined area, impeding the lost of nutrients and organic matter for the rainfall, which were retained in the concavities. Besides that, this technique propitiated the creation of micro-habitats which could favor a larger interaction among soil, plants and animals leading to an increase of the biodiversity within the system

ASSUNTO(S)

mimosa scabrella engenharias recuperação de áreas degradadas floristic florística reclamation of degraded areas mimosa scabrella

ACESSO AO ARTIGO

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