This research was developed in the Agroforestry Unit of the "Companhia Mineira de Metais (CMM)", Vazante, Minas Gerais, Brazil, to study microbial activity in different ecosystems such as agroforests, monocultures, deforested areas and native forests using the method of respirometry under laboratory conditions and CO2 evaluation rate evolution under field conditions. Biological activity showed accumulated values of respiration rates at 20 days of 3.56 to 6.03 meq C-CO2/100 g of soil in the laboratory, and 165.16 to 559.37 mg CO2/m-2.h in the field, in deforested area and native forest, respectively. Activity was higher in native forest and pasture than in monoculture or agroforestry, in both experiments. Microbial activity was higher in agroforestry with rice and eucalypt than with rice in monoculture, under field conditions.
Agroforestry; monocultures; soil respiration
