The main objective of the research is to evaluate the hypothesis that low input pasture use of land with Brachiaria spp. can sustain cattle systems in the western Brazilian Amazon without deteriorating soil resource stocks. Land cover types evaluated included forest, maize and rice, B. decumbens and B. brizantha grasses, and a grass association with Pueraria phaseoloides. We sought to estimate temporal changes in the physical and chemical properties of soils and forages from pasturelands of different ages (i.e., time post-deforestation). The ultimate goal was to determine the essential nutrient management to enhance cattle productivity and to avoid degradation of pasture land.