Soil organic carbon stocks and fractions under integrated systems and pasture in the Cerrado of Northeast Brazil

•Soil carbon stocks were measured across land-uses in the Cerrado of Northeast Brazil.•Integrated crop-livestock systems increase soil C and N stocks.•Long-term continuous input of plant residues governs C and N stabilization.•Integrated systems can sequester C in soils of Cerrado in Northeast Brazil. The adoption of integrated systems can reduce the pressure for the conversion of areas under native Cerrado to agricultural lands. However, little is known about how these systems affect total organic carbon pools and stocks in the Cerrado of Northeast Brazil. We aimed to evaluate the dynamics of soil organic carbon (SOC) and C and N stocks in a Cerrado under different cropping systems, in the agricultural frontier of Matopiba, Brazil. The systems were (i) Native Cerrado vegetation (NCF), (ii) integrated crop-livestock-forest system (ICLF), (iii) integrated crop-livestock system under no-tillage (ICL1), (iv) integrated crop-livestock with recent soil tillage (ICL2), and (v) pasture (PA). Soil samples were collected at 0.0–0.10, 0.10–0.20, 0.20–0.30, and 0.30–0.50 m depths to determine the soil C and N stocks, SOC fractions, and the carbon management index (CMI). Total C stocks in the 0.0–0.50 m soil profile were highest in ICL2 (127 Mg ha−1), ICL1 (112 Mg ha−1), and PA (101 Mg ha−1) and lowest in NCF (61 Mg ha−1) and ICLF (67 Mg ha−1). Similarly, total N stocks were highest in ICL1 (6.7 Mg ha−1), PA (6.7 Mg ha−1) and ICL2 (6.5 Mg ha−1), and lowest in NCF (4.7 Mg ha−1) and ICLF (4.8 Mg ha−1). ICL2 and ICL1 presented the greatest amount of humic fractions among the systems. The adoption of conservationist management systems that provide a permanent input of organic residues in the long-term is crucial for SOC stabilization and increases in soil C and N stocks. Integrated crop-livestock systems are the most suitable alternative for sequestering C and N in grain production systems in the Cerrado of Matopiba region.