ChileanJAR

Leguminous trees are being planted in order to establish restoration units in the Brazilian Atlantic forest ecosystem. The success of the establishment depends on the growth, productivity of plants and litter decomposition rates. The objective of this study was to investigate the decomposition of araribá (Centrolobium tomentosum Guill. Ex Benth) leaves, at two sites. Site 1 was an experimental plantation of the native species C. tomentosum, which was inoculated with rhizobia plus mycorrhizal fungi, and Site 2 was a eucalyptus (Eucalyptus grandis W. Hill ex Maiden) forest. The leaf litter of C. tomentosum was incubated for 120, 240 and 360 days in both sites. The decomposition rate and dynamic of mineralization of the organic matter and the nutrients K, Mg, Ca dynamics were modified by the site effect. The remaining mass and nutrient content were lower in Site 2 than Site 1. The N and P immobilization occurred eight months after incubation in Site 2 and four months in Site 1. Microbial colonization was made by fungi in Site 2, while in Site 1 the bacteria colonization was higher. The high soil content of Cu, Mn and Zn in Site 2 was not correlated with the metal levels in the residues. The content of Cu and Mn in residues increased in the two sites. Change of eucalyptus plants to trees of C. tomentosum modified the soil biota and favored the bacteria in comparison to fungi.