Humidified fractions of organic matter and soil microorganism populations are used as environmental quality indicators. This work aimed to study the changes in chemical and microbiological soil attributes, as well as in the humidified fractions, of the organic matter in a substrate from a clay extraction area cropped with Brachiaria mutica, Acacia mangium and Eucalyptus. In the Eucalyptus area, the P contents increased linearly with planting time. However, only at the twelfth year, differences between Eucalyptus and B. mutica areas have occurred. In the A. mangium area, such differences in the P content occurred at the third year with increment of 43%, at the 0-10 cm layer, in relation to B. mutica. Also, at the 0-10 cm layer, the total carbon contents... |