Integrated crop-livestock-forest (ICLF) systems has been considered as an important strategy to enhance C sequestration. However, changes in soil C due to agricultural management practices, in general, are observed in long-term experiments. Our objective was to investigate short-term impacts on soil organic matter under different management systems in the Cerrado/Amazonia region. Treatments corresponded to ICLF, No-tillage, Pasture and Eucalyptus plantation. Soil was sampled in 2014, in the 0-5, 5-10 and 10-30 cm layers for quantification of light- and heavy-fraction C stocks as well as their C isotopic composition (DELTA 13C). After three years established, all evaluated treatments showed similar values of light- and heavy-fraction C stocks to those observed under Native Forest in the 0-30 cm layer. Under Pasture and ILCF treatments, we observed that most of C of the light-fraction was substituted by pasturederived C in the uppermost soil layer (0-5 cm). Despite no differences in heavyand light-fraction C, the application of 13C stable isotope technique seems to be an important tool to evaluate short-term C turnover under agricultural systems
