Relações entre atributos do solo e a vegetação espontânea para indicação de práticas no reflorestamento em solos de Mar de Morros

Abstract

Knowledge on the relationship between soil and plant species is fundamental to restoration projects in view of the dynamics of succession, since the invasive species may turn the projects very expensive or impractical. Control practices of the invasive plant species based on natural conservation may add to recovery measures, thus reducing the costs and increasing their efficiency. The aims of this study were to investigate relationships between different soil types and the occurrence of thatch (Imperata brasiliensis) plants in two different areas on the IFRJ Pinheiral Campus (Pinheiral-RJ); and to evaluate the use of forage legumes and their efficiency in the control of the invasive vegetation, associated to the use of direct seeding and planting of seedlings in reforestation activities. Eight trenches were evaluated in two toposequences, through characterization of soil properties and dry mass of shoots and roots of thatch sampled in four soil layers, respectively 0-7, 7-14, 14-28 and 28-35 cm. The eight soil profiles were also classified according to the Brazilian system. There were evaluated the heights, diameters and survival of seedlings of five forest species, subject to two forms of planting, tillage and seedlings, and two planting densities of sunn hemp legumes, pigeon pea and pork beans, as well as the efficiency of these plants in reducing the weed competition. The soil properties did not influence the behavior of the dry mass of the thatch, and the difference between the dry weight of roots and shoots between the two toposequences is possibly due to shading by existing eucalyptus stand in the second area. The legume plants combination did not differ regarding the influence on the native species, neither on the weed control. There was significant difference only when compared the average of the four treatments. Possibly, the use of different legumes planting forms and conducting more experiments could show an increase in their efficiency. The planting method using seedlings of the forest species differed significantly and it was more efficient than the direct planting of the seeds, showing to be the most suitable for the local situation.