Simulation of soil carbon and nitrogen stocks in conservation systems in Cerrado of Northeastern Brazil

Aim of study: Conservation management is an important alternative for the mitigation of environmental problems caused by conventional agriculture; however, information about long-term benefits of conservation systems is still incipient. Simulation modeling of soil organic matter dynamics has been applied using different types of land use and management. The models are essential tools for building scenarios for sustainable production systems. This study aims to use the Century model to simulate the effects of no-till and integrated crop-livestock system on soil carbon and nitrogen stocks and to establish scenarios in sandy soils at the Cerrado Brazil. Area of study: Barbosa Farm in the municipality of Brejo, eastern Maranhão state, Northeastern Brazil. Material and methods: An area that has been under no-till farming for fourteen years (NT), an area under both no-till and crop-livestock integration (NT-CLI), and an area under native Cerrado vegetation (reference) were selected. In each area, simulations of real scenarios and three future scenarios were carried out. Main results: The simulated total organic carbon (TOC) stock values for the real scenarios were 41.15 Mg ha-1 and 44.91 Mg ha-1 with NT and NT-CLI systems, respectively; whilst for simulated total nitrogen (TN) stock were 2.29 Mg ha-1 with NT and 2.59 Mg ha-1 with NT-CLI systems. However, TOC values were more accurate compared to TN values. The complexity of TN dynamics may not be fully represented by the simulation. Research highlights: Models show that future scenarios up to 2060, integrated crop-livestock system were more effective, storing up to 85.92 Mg ha-1 of TOC stock and 8.94 Mg ha-1 of TN stock.