The influence of reforestation was evaluated during two season periods (February and October) in sites planted with Corymbia citriodora and Leucaena_leucocephala through microorganism counts (bacteria, fungi, actinomycetes, and nitrite oxidizers) and microbial activity (respiratory and urease activities). An Atlantic forest and a bare soil site were used as controls. The general trends of the variables in the different soils were: Atlantic forest or L. leucocephala > C. citriodora > bare soil. The microbial populations in L. leucocephala and C. citriodora soils were significantly higher (P < 0.05) than that found in the bare soil. Similar results were obtained for respiratory and urease activities. The microbiological variables of the soil under L. leucocephala were comparable or even superior to that found under Atlantic forest. An improvement in the microbiological soil variables was observed in the soil under C. citriodora when compared to the soil without vegetation. These results can be attributed to an increasing amount of total organic C of the soils under L. leucocephala and C. citriodora in relation to the soil without vegetation. Although most results obtained in February presented higher values than in October, the sampling period did not have a consistent controlling influence on these variables.
bacteria; fungi; forest degradation; respiratory activity; urease