Soil organic matter (SOM) is recognized as an important characteristic of sustainable agricultural systems in the tropics and temperate regions. It is considered an integrated characteristic of physical, chemical and biological soil conditions and has been used as a soil quality index in different land uses and management practices (Lal 2011). Environmental, social, and financial imbalances have occurred, requiring producers to become more efficient. A system of intercropping grain crops with forages can provide enough forage in the dry season to maintain nutritional quality of livestock and even promote weight gain (Castro Filho et al. 1991). An integrated crop-livestock system (ICLS) that includes a crop phase and a pasture phase in rotation has strong potential for sustainable beef and grain crop production (Salton et al. 2011). Perennial pastures can contribute to soil C sequestration. Several studies have shown significant soil organic C accumulation with well-managed grazing of pastures (Maia et al. 2009; Salton et al. 2011). However, there are few studies that compare the efficiency of different grasses to maintain productivity and promote an increase in soil organic C and stocks. We hypothesized that an ICLS with maize cultivated under no-tillage in rotation with grazed pasture (Urochloa P. Beauv. spp. (syn. Brachiaria (Trin.) Griseb. spp.) would result in accumulation of soil organic C and N compared with continuously grazed, degraded pasture or with conventionally tilled monoculture production of maize. Our objective was to evaluate the stocks of soil organic C and N under alternative land uses from the prevailing degraded pasture condition in Sao Paulo state of Brazil
